Well the chances for you to get CSE depends on your SASTRA rank. If you are in the first 500 ranks you can get a CSE seat for sure. A lot of people might have got more than 89 percentile in JEE.

The admission solely depends on merit and the the percentile of other students. And one thing more If you get a cgpa of around 8.5 in your first year, you can slide to CSE.

Hope it helps!!

Best of luck and god bless!