I have friends studying at NIT Calicut, and according to them, the classes usually begin from around 8 A.M. However, it is not mandatory to have a class during the very first hour when the institute commences. Depending upon your timetable and batch, the classes can accordingly vary.
You can have a total of 3 to 4 hours of class periods and it might still commence from around 10.15 A.M, depending upon whether or not you have been allotted the slot with other members of your class.