Unique is what I used when I first started loading 9mm because I had some on hand from shotshell loading. The data for loads with Unique varies quite a bit depending on whose manual you are looking at. In general, most of the loads shown in the MAP books are lighter than those put out by others, but they claim that their max loads are the Maximum Average Pressure allowed by ANSI/SAAMI specs according to their testing. They start light and work up by 1/10 grain increments giving psi and fps for each load.
The Midway LoadMAP shows a starting load of 4.4 grains with the Rem 115 fmj up to a max load of 5.4, which they say is a compressed load.
The Nosler manual shows loads for their 115 grain bullets as being from 5.1 grains up to a max of 6.1.
The Lee manual data for 115 grain jacketed bullets over Unique starts at 5.8 and is max at 6.1.
I used 5.1 grains of Unique to push various 115 grain bullets and it worked pretty good. Recoil was light and I could have set a bucket out to catch all of my brass. No, Unique is not the cleanest burning powder for the 9, but I have shot some of the cheaper factory ammo that was dirtier.
I am currently using Titegroup for most of my 9mm loading. I picked it up from a vendor at a gunshow for about $5 less a pound than most powder available locally. It burns cleaner, meters nicely, and at the price I paid, I should have bought a lot more.