91 %tile, OBC can get any IIT ?
For IIT you have to qualify the JEE MAINS cut off and then have to go for JEE ADVANCED. If you qualify JEE ADVANCED then only you will get a seat at IIT.
With the percentile you have provided and with your category you have good chance for NIT's.
For college predictor you can visit the link below:
https://engineering.careers360.com/jee-main-college-predictor?icn=QnA&ici=qna_answer
I hope this answer helps. All the very best for your future endeavors!