You can do whatever you want really with flashing.
When you say soft/throttle body I think you mean the secondary throttles - yes you can alter under what rpm & throttle position conditions they do what at.
But the secondaries table only goes to 6000rpm, even in the special 9000rpm (fuel, ignition and rev limit) maps Alain made for us - probably because nobody really has any interest ime in dampening power delivery up high in the revs, at least beyond 6000rpm.
The bike will indeed shine brighter at 8500 rpm but you do NOT want to do this without some serious work on the head first, e.g. converting to shim under bucket like a sport bike so it don't spit a shim out under high rpm, stronger springs so the valves will close quick enough at higher rpm and the piston won't hammer them, lighter retainers and/or valves so that the whole assembly being moved is lighter and can/will close on time i.e. not suffer valve float.
Plus the stock cams run out of puff long long before 8500 anyway so you would also need cams so the engine can aspirate at higher rpm, or the bike can rev all it wants but will actually make less and less power the higher you rev it.
Another thing to be aware of running that high rpm is piston speed, I've not seen any factory engine (or even F1 cars) rev over 25m/s. Only modified track oriented builds where milking the engine for power is par for the course.
Forged and lighter if possible pistons would be a good idea.