Looking at St.Dominics Savio Model High School in Nacharam for class 9, as his current school ends at 8

Our son is in class 8 at a small school that only runs up to class 8, so we have to find a place for class 9 whether we like it or not. He wants to stay on State Board and stay close to home, and in Nacharam that makes St.Dominics Savio Model High School one of the obvious ones to look at. Two things I have not been able to find out. Do they take children into class 9, or is it mostly students who have been there since the lower classes? And if they do, is there a written test, and roughly when does that happen? Would like to hear from any parent whose child joined there in the higher classes.