Do I need to report at exact reporting time that is 8 in my admit card or can I reach by 8:30? Exam will start at 9:30.

The exam time is mentioned seeing all the students. If they write that you can also come at 8:30. Then nobody will reach the centre at 8:00 and after 8:30 the gathering will increase exponentially. You can reach at that time too. But they mention more time gap so that they could check the candidate