Do yourself a favor and just go with a 1-8 twist (easier to find in aftermarket barrels anyway). Even with the 1-8 twist you'll still be able to shoot most bullets down into the 45-50gr range and it will better stabilize the heavier/longer 75-80gr bullets.

That said, I had one of the first fast twist (1-9) Model 12 LRPV's to leave the factory (was actually a pre-production model) and it shot the 75gr Amax's amazingly well. The 80 grain Amax's had just come out at that time and I gave them a try, but they didn't shoot nearly as well as the 75's did. It would shoot the 52/53gr Match bullets like a house of fire as well if you like to play the short games on occasion to.