St. Xaviers Ahmedabad is an autonomous college . Its basic admission criteria is merit based . You can apply online for it and yes they have scholarship process as well .
About the cut off 2019 , it is yet not out .
Registration for BSC starts from 15th May 2019 and ends on 02 July 2019.
Still if you want to have an idea about your eligibity and cut off o St. Xavier , you can have a look at BSC cut off 2018 .
I hope I was helpful