Do I need a hardened intermediate shaft for a HV oil pump?

When installing the intermediate shaft bushing per factory spec, you do not "ream" the bushing at all, best descriptor I can think of is a combination of rolling and burnishing. The rolling action locks the bushing in place by expanding it and the burnishing action smooths the interior and size's it. If you're reaming and cutting metal; you're doing something wrong.

Running a hardened intermediate shaft is never a bad idea.

Don't have the tool? Get friendly with the service manager at your local Chyrslier dealer and borrow theirs.