Cpt. I'm surprised that you noticed big difference between 9 & 10" brakes...
My case: Ranger A with 9" is RC/SB with manual, while Ranger B with 10" is RC/LB with auto. And Ranger A stops better with clutch in, than Ranger B which I leave in drive. (Ranger A is actually heavier as it has bed liner and a/c, same engines).
Note: Ranger C with V-6 Mustang rear discs actually stops the worst even with premium pads & rotors. Biggest waste of time and money I have done with one of my Rangers.
(And yes, I have too many RBVs - comes with 2 teenage kids of my own, 2 teenage nieces, brother-in-law and me all wanting cheap transportation).
Back to problem at hand. If troymn wants to go to the effort of removing the differential cover, removing the axles, then he can unbolt the 9'' brakes from his 7.5" differential. Then repeating with the 8.8" will allow him to swap axles without having to bleed the brakes assuming he has unclipped the brake lines. Then he can bolt the existing brakes to the new housing, reinstall the axle, fill with fluids and be good to go. And at the end, he will have an 8.8" differential with limited slip and 9" drums.
I do agree with Cpt. keep the 10" stuff around and when the 9" wears out, swap back to the bigger stuff.