Indian Creek, I load both on a Dillon 550. There are lots of great powders. But I really like Unique for the 45Colt and Bullseye for the 9mm. Trail Boss is also awesome for the 45Colt. And Pistol CFE is also really good for the 9mm. Grab a good loading manual and pick a recipe. Follow the load "work up" as explained in the manual. You won't go wrong.
Hi, Indian. And welcome. I shoot a Henry lever in .45 Colt, and Unique is indeed, a great powder to start with there. I use a lot of TiteGroup in my 9mm and it works well for me, but there are lots of choices. If you have a Lyman manual, they indicate which powders they found most accurate for each bullet. You will note that different bullets within the same caliber favor different powders.
There is really no ‘best powder’ to start with that will perform equally well with both 45 Colt and 9mm, but there are some that are listed for both. That said, you can’t go wrong with Unique for the lever gun, and there are load data for Unique in 9mm.
Hi Indian Creek, welcome to "Highboy Nation" the best gun forum on the Wide, Wide world of the Internet. Glad you could join the group.
As for powder for the 45 Colt, I use Unique. 9mm there are many options. I agree with Walter and the others. You just need a good reloading manual and follow the recipe. Start lower on powder charges and work your way up safely. Try several powders to see what works best in your handgun.