Hello student no matter you're from which state you'll get the domicile of the state from where you did your senior secondary school (+2) as you said you did your class 12 from West Bengal then yes you'll comes under West Bengal domicile. And if you comes under physically disabled candidate then all you need a certificate no matter its from which state.

You can also make your physically disabled certificate in West Bengal incase you face any difficulties.

Feel free to comment if you have any doubt

Good luck