10.5-1 isn't all that high of compression. Like The Dog33 said, 92 octane is fine and you can probably use 89 as well. BTW, yes, I have a 904 kit in my bike too and I have the same compression you do. Like I said before, if you want to throw your money away feel free to do so.
Also, higher octane fuels will not burn as completely if your compression isn't high enough to need them (which it isn't) and they will leave carbon deposits on your pistons, valves, and combustion chambers. Not good.
