You can get in that MV range with about any of the faster pistol powders - Bullseye, Clays, Unique, Green Dot, AA#2, 231. It would take some experimenting with a chronograph.
My internal ballistics program suggests 8.5 grains of Bullseye, 9.2 grains of Unique, 8.8 grains of Green Dot, 8.0 grains for Clays, 9.1 grains of AA#2, and 9.1 grains of 231 to get the 900 ft/sec MV you want. All peak chamber pressures are FAR below maximum in .454 cases.
I am sure Trail Boss is a fine propellant for some applications requiring a bulk powder that fills the case. But it sure isn't very economical, at least double the cost (or more). I have always avoided it for that reason. I always visually check every single charged case before bullet seating to ensure there are no double charges when using conventional pistol powders, so Trail Boss is superfluous. I use Bullseye or Unique for almost everything. It's all I need.