Navarātri is popularly considered to be 9 days dedicated to the worship of Navadurgā i.e 9 forms of Bhagavatī Durgā. However the Devi-Bhāgavata Purāna, which describes the procedure of Navarātri vrata, has no mention of Navadurgā. The only mention of Navadurgā found till now is in the Kālikā Purāna where they are simply described as āvaraṇa devatās of Kāmakhyā while being worshipped in the sacred Yonimaṇḍala of Kāmarūpa but nothing about their iconography or association with Navarātri. So can anybody cite any valid scriptural reference for Navadurgā worship during Navaratri ?
Durga saptshati has multiple mentions of Navdurga.
When Markandeya ji asks for Durga kavach mantra, Brahma ji describes nine form of Durga or Navdurga.
- Shailputri / Parvati : fear and sorrow goes away by her darshan. Daughter of Himalaya.
- Brahmacharini : who continuously seeks Brahma
- Chandraghanta : Moon resides in who's Ghanta
- Kushmanda : this warm Universe resides in who's abdomen
- Skandamata : mother of Skanda
- Katyayani : daughter of Rishi Katya
- Kaalratri : destroyer of Kaal(death)
- Mahagauri : who received great Gaur varna by tapasya
- Siddhidatri : who gives Moksha
I do not know what is the connection between Navadurgas and Navratri. This is an interesting question.
However, Navadurgas are not only mentioned in Kalika Purana. They are also mentioned in the Skanda Purana. After Sati's death, they were sent along with Virabhadra, Bhutas, Ganas, Yoginis etc.
Expressly commanded by Rudra himself the extremely powerful Vīrabhadra came to the sacrificial enclosure accompanied by the nine Durgās and others. The nine Durgās were Kālī, Kātyāyanī, Īśānā, Cāmuṇḍā, Muṇḍamardinī, Bhadrakālī, Bhadrā, Tvaritā and Vaiṣṇavī. A big multitude of Bhūtas also entered the sacrificial enclosure of great refulgence. Śākinīs, Ḍākinīs, Bhūtas, Pramathas, Guhyakas, a host of Yoginīs (in circular formation) along with the sixty-four (Tantras) — all these entered the sacrificial enclosure suddenly. - Skanda Purana I.1.3.49-51