It will have a removable center section (from the front) and the way to tell if it is an 8 inch vs 9 inch (they look very similar) is to put a deepwell socket on the two bottom bolts that hold that center section on. If the socket goes on, it is an 8 incher. If it hits the casting and won't clear (so you need a box end wrench to remove them) it is a 9 incher.

Don