The 9 1/4 has axle shafts with the "C" clips to hold the axle in the housing. Those rear ends also have the wheel bearings run on a machined part of the axle itself. If you remove 2" off the end of each axle, you will remove the method the axle was retained, and you will remove most of the axle splines, but then you probably will need to come up with a way to hold the axle in the housing because you never had the pressed on wheel bearings, they always rolled on the axle shafts themselves. I don't know if the performance aftermarket axle shaft companies have replacement narrowed axle shafts for a 9 1/4".

An 8 3/4 or even a 9 3/4 might be a better option if you want to narrow the rear end.

The brake backing plates bolt onto the 8 1/4, the 8 3/4, the 9 1/4, and the 9 3/4. And if the wheel bolt pattern are the same, the brake drums follow the same brake size across the axle choice.

So someone is going to tell you I missed something, I'm blaming my memory.