CBSE 10th

Check out this link for previous year's cutoff according to colleges -
https://www.shiksha.com/minimum-cat-2015-percentile-required-for-admissions-at-iims-article-11265-1
At 90 percentile you can apply for BIM-Trichy, GIM-Goa , IFMR-Chennai and few others, but these are some good colleges. IFMR is known for Finance among corporate and it is at par with IIMs with 100% placement record. GIM-Goa is having good past track record and BIM-trichy is upcoming with disciplined study culture and decent placement record.

600 score in CAT is compulsory for Christ.

The criteria of shortlisting is profile based

You need above 60%. You should try to get above 80%, it will help you in future.

You should pursue MBA. Try to score more than 97 percentile in management entrance exam. MS is also a good option if you score more than 32 marks in GRE exam. If you want to stick to the technical field, then opt for M.Tech, but competition is very tough for that as there are very few ace colleges for pursuing M.Tech.

As you are asking for entrance exams, you should first decide which course you want to pursue.
As per your marks I suggest you to opt for BBA or BCA.
If you are interested in science stream, opt for B.Sc in IT or computer applications.

You can opt for science stream if you want to make your career in the technical field. You can opt for arts stream if you want to pursue LLB or MA.

to expect a call from iim you have to give cat entrance exam and should score at least 98 percentile in the same

Hello Raj,
You can do your 12th from open schooling like from NIOS and after that you can join any institute or college for your higher studies.
Please visit NIOS and fill up your form.