Mahanavami is celebrated on Ashwin Shukla Paksha Navami, the ninth day of Durga Navratri. In 2009, the date of Mahanavami is September 27. Maha Navami is the last day of 9-day festival, Sharad Navaratri. As per Hindu beliefs, Durga puja on Maha Navami is equal to Durga pooja performed on all 9 days of Durga Navaratri. Goddess Siddhidatri puja is performed on Mahanavami day.
On Mahanavami day, in South Indian states especially in Kerala, Ayudha Pooja(workship of tools) is performed. Tools, operators, instruments and books are worshipped. The next day of Mahanavami is observed as Vijaya Dashami. In some rural places, Janthu bali (animal sacrifices) are performed on Mahanavami day. It is to be noted that Hindu culture and society is against animal sacrifices.

Vidyarambham 2009(Vijaya Dashami) – Ezhuthiniruthu during Durga Navratri in Kerala
Vidyarambham or Ezhuthiniruthu is one of the main rituals observed during Durga Navaratri Pooja in Kerala. In 2009, the date of Vidyarambham is September 28. Vidyarambham puja is performed on Vijaya Dashami day which falls in the Malayalam month of Kanni.
On Vijaya Dashami day in Kerala children between two and three or five years old are initiated into the world of knowledge with Vidyarambham pooja. Vidyarambham means ‘initiation of knowledge gaining’.
After Vidyarambham puja, slates and other stationary items are distributed by the child who has done with Vidyarambham to some other children. The distribution of the items varies from place to place. In Kerala, Vidyarambham or Ezhuthiniruthu is performed by the people irrespective of their caste and religion.
Ezhuthiniruthu is the grand celebration in Panachikkada Saraswathi temple in kottayam Thiruvullakkavu in Thrissur and the Mookambika Temple Vadakkan Paravur Temple in Ernakulam district of Kerala.

'Nava-ratri' is one of the most celebrated festivals of Hindu calendar. It is celebrated with immense zeal and enthusiasm all over the country. Like all Indian festivals, there are many legends attached to the conception of Navratri. All of them are related to Goddess Shakti (Hindu Mother Goddess) and her various forms.

Navartra literally means "nine auspicious nights." It is actually the worship of the Goddess of Power in order to seek her protection from any possible kind of threat and calamities that may destroy the peaceful life of people on earth. As she is the Goddess of Power, she is believed to have the power of creation, preservation, and destruction.

Navaratri is separated into sets of three days. These sets are made in order to adore different facets of the supreme Goddess. On the initial three days, the Goddess is invoked as the supreme powerful force called Durga. Goddess Durga is meant to all our contaminations, evils, and defects. On the next three days, she is worshipped as the mother of spiritual wealth, Goddess Lakshmi. She is the one who is considered to have the power of showering on her devotees with the blessings of never-ending wealth. In the final set of three days, the Goddess is worshipped as the Goddess of Wisdom, Saraswati, responsible for spiritual enlightenment and overall success in life.

The Goddess is also worshipped under nine different names for the nine days in Navratri. Every day, she assumes a new character, a new look, and a new duty. She is worshipped as Shailputri, Brahmacharini, Chandraghanta, Kushmanda, Skanda Mata, Katyayani, Kalratri, Maha Gauri, and Siddhidatri. For the initial six days, the Pooja celebrations are limited to home. The celebrations acquire a festive form since the seventh day when the festivities of Navratri surround the atmosphere.

First Day Pooja
The first form of Goddess Durga is called Shailputri . She is considered the daughter of the Himalayas. She is a form of Shakti, the consort of Lord Shiva.

Second Day Pooja
The second form of Goddess Durga is known as 'Brahmacharini'. Her name is derivative of the word 'Brahma', which means 'Tapa' or penace. She is also a form of Uma or Parvati, a form of Mata Shakti.

Third Day Pooja
On the third day the goddess is worshipped as Chandraghanta. She is the symbolic representation of beauty and bravery.

Fourth Day Pooja
Kushmanda, is the form of the goddess which is worshipped on the fourth day. It is believed that Kushmanda is the creator of the entire Universe and she has created the entire Universe by her laugh.

Fifth Day Pooja
On the fifth day, the form of Goddess is called Skand Mata. She is actually called so because she is here represented as the mother of Skanda, the chief warrior of the Gods army.

Sixth Day Pooja
On the sixth day, the goddess is worshipped as Katyayani. Seated on her vehicle lion, Katyayani has three eyes and four hands.

Seventh Day Pooja
On the seventh day, the Goddess is worshipped as 'Kalratri'. As the name suggests, Kalrati is as black as a dark night. She has four hands, she is meant to make the devotees fearless.

Eighth Day Pooja
On the eight day, the Mata Rani is worshipped as 'Maha Gauri'. She is considered to extremely beautiful, white like snow and accessorized with white colored ornaments. She represents calmness and exhibits wisdom.

Ninth Day Pooja
On the ninth day, Durga is worshipped as Siddhidatri. It is believed she consists of all the eight siddhis. She lives on lotus and is worshipped by all the Rishis-Munis, Siddhas, Sadhakas and Yogis.

During these nine days of festival, people undergo rigorous fasts. The festival culminates on Mahanavami. On this day, Kanya Puja is performed. Nine young girls representing the nine forms of Goddess Durga are worshiped. Their feet are washed as a mark of respect for the Goddess and then they are offered new clothes as gifts by the worshiper. This ritual is performed in most parts of the country. Devotees of Goddess Durga perform this pooja offering fruits ,beaten rice, roasted paddy and jaggery. Devotees sing devotional songs and indulge in the celebrations of Navratri.

On the Durgashtami day a ceremony called Poojavaipu is performed in the evening. It is done only in certain households, in temples, and also sometimes in the schools. The Brahmin houses and the houses which enjoy reputation for learning mainly take the lead in celebrating the festival. The members of other houses in the village attend the ceremony performed in these houses or institutions.

For the pooja, books and grandhas (holy books) are arranged with an image of Goddess Saraswathi in front in a well-decorated room. Weapons and implements are kept by the side of books and grandhas. Then a Puja is performed to Saraswathi during which fruits, beaten rice, roasted paddy (malar), jaggery, and so on are offered to the Goddess. These offerings are distributed among those present when the Pooja is over. Just before the Pujavaipu, all studies and work which mainly require skill are suspended. There are certain communities which celebrate the festival on all days of Navarathri. Images of Gods, animals, and toys of different variety are arranged for exhibition and this performance is called 'Koluvaipu'.

The following day is known as Mahanavami and it is totally devoted to the worship of Saraswathi. Pooja is performed both in the morning and in the evening. Many more items such as rice, payasam, thirali are also offered to the Goddess along with the items mentioned above.

On the Vijayadasami day in the morning, the Books and implements are removed from the room and this ceremony is called "Pooja Eduppu." The time for the break up of the pooja marks the beginning of learning and work. Learning and work commence at this auspicious moment. At this moment, the children for the first time are given instructions to write the first few alphabets on rice or sand. They are thus initiated into the world of knowledge. This is known as "Ezhuthinu Iruthu" or "Vidyarambham." According to custom, only after this ceremony child becomes entitled to write or read.

The main celebration of Navaratri is at Sree Padmanabha Swami Temple at Thiruvananthapuram. Apart form the usual poojas and rituals, classical music recitals are held on the Navarathri mandapam every night during the festival in which celebreties of Carnatic music participate. This cultural event was started by Maharaja Swathithirunal.