An 8.75 will handle a ton if a few things are in it in my opinion.I'f a trans brake is used it'll bust the stock caps after a while.
I built the 8.75 rear in my cuda the best it could be built Mark Williams caps,35 spline axles and we braced it end to end.The only thing that i believe was a little weak was the size of the ring and pinion.
The only reason i went with a bullet proof 9" was i was working alot of OT and could swing the cost...lol.All joking aside i did it because its 1 less thing to worry about,and the same reason i went with an ATI sfi full aluminum case in my glide.