Reusing granite after kitchen island failed.

I was trying to do a moveable island that could slide into the corner when not in use but the plywood underneath the feet didn't handle the weight good so it collapsed. :o After repairing it I moved those same cabinets against the corner and attached them to the wall. The whole set of cabinets has 1/2 hardiboard all around ( was going to do a tile design on island) and it is attached to the wall via metal L shaped an corner plates. In most of the places with the l shaped and corner a hardiboard screw goes into the stud currently. Now I have a 1/2" plywood followed by 1/2" hardiboard and then 1/2" granite that was being designed for a moveable island but will now hang off 10" past the edge of the cabinets. Do I need to support this even more underneath the counters? Its about 98"Lx 34"W.