A 9mm is definitely more comfortable for small framed carry. However, you will find that the best 9mm for steel challenge is a .40 or .45. :lol: :lol:
Due to the added capacity of mags w/ smaller diameter rounds, you'll likely have an extra round or two to RE-SHOOT those steels that don't spin/flop/drop on the first clang. But you will recover from each shot quicker if the pistol weight and your hand/arm weight are sufficient. Just don't lift your foot to run to the next station until you're sure the steel is down.
I often carry a nine due to size, weight, dress, & of course, comfort. But projectile size matters at times. Good Luck.
GUNSMOAK