Depends on how long you want the motor to last.
1) Just get an aftermarket ECU and set the rev limiter to 9k. Buy motor shortly after
or
2) Rebuild engine with necessary components to handle 9k. Probably need new rods, lighter pistons and block girdle. Balance the entire rotating assembly. Now for the head you'll need to either lighten the valve train or get way stiffer springs. Probably a combination of both. May need a cam profile that will allow the engine to pull that high and still rework the ECU. Much more to it but that's the majority of it.
