Hello Amit!
Congratulations on your rank! 991 is a decent rank and with this rank, you can choose any branch of engineering you want to choose in KIIT. If you are inclined towards software engineering, you can choose Computer Science Engineering. If you are inclined towards electrical branches, you can choose Electrical and Electroics engineering etc. Since you have got such a good rank, you can prefer any branch you want to choose. Hope this answer helps.
All the best!