Pretty sure if you were running up around 9000 RPM, you would need to have your cylinder head modified first, so you can convert to shim under bucket, and stronger valve springs, before you could safely rev to 9000 RPM.
Otherwise it will spit the shims out and valves will get piston hammered.
Also would probably need different cams as the stock ones max out around 6000 RPM so there'd be no point in revving past 6-6500 with stock cams. Power would die off after 6500.
Ideally you'd also have lighter pistons and valves fitted too so they don't have as much inertia and engine can spin up faster.
Basically if you run at 9000 RPM with stock engine it will probably be destroyed shortly after and suddenly.
Just My opinion ??