Why do you want to rev it?

You can rev an EJ207 to 8500rpm all day every day. Most turbos start dropping off around 7k, so why would you want to rev it any higher??

The stock crankshaft becomes marginal at constant use above 8500rpm, and requires mods to be reliable above 9000rpm.

You will need to run an aftermarket or a shimmed stock oil pump to increase oil pressure, and possibly even a cross drilled crank because centrifugal force throws oil away from the crank journals at really high RPM in a Subaru.