No percentile can ensure you admission in IIMs. You will only get calls for the next round. And different IIMs have different criterias for cut-off and hence the cut-off also varies. For the top IIMs an average score of 99+ percentile is required provided you have good academic background as well. For the newer IIMs, a score of 96+ will suffice.

All the best!

All the IIMs need more than 90 percentile in CAT to get admitted.