Answer
The part that actually needs attention is the IBM i operating system release, not the application code. Each Power generation supports a minimum IBM i release, so if your Power 9 partition is running an older release, the migration plan may need to include an OS upgrade before or during the hardware move. Third-party integrations pinned to a specific PTF level or Java runtime are the other place to check, since those are more likely to need revalidation than the RPG or COBOL source itself.