Hodgdon Universal, I load 38 special, 45 auto, and my 9mm all out of the same powder. 125 grain round nose, 4.5 grains Universal, 1.135 OAL, that's the start load out of the Speer manual and it runs fine for me.
Actually got the info from one of the periodicals I read. Handloader magazine. Granted it often covers very esoteric subjects such as handloading cast bullets in 25-20 WCF lever action rifles, there are nuggets of info that are useful for the rest of us.
Back on topic as to what is your go to powder for 9mm. During this last component shortage I got the wild hair to go through my stash and see what I had available to load 9mm. Came up with 6 powders and 3 primers. In a fit of drunken rage decided to work up loads for each. Probably will take me the rest of the year to finish the project.
Results so far are interesting. My go to primer is Winchester. However Federal primers across the board results in a slightly lower velocity and power factor. The upside is the SD and ES are also lower. Have CCI primers on the shelf and waiting to see how they fair at the chrono. When its all done I'll get the info out.
Bullseye , Red Dot , 700X or Unique.
All have been just fine with mostly cast bullets.
Would also try CFE pistol if I could get some, heard good reports.