Chosen Solution

Is it possible to replace just the keyboard on this machine? It’s done a lot of typing and the home keys have started acting intermittently. I’d rather not replace the whole top case if possible. I’ve already popped the keys and cleaned out the underside of them but that had little effect.

Yes, you can replace the keyboard alone. You’ll need to look on eBay to find one for your exact model. Follow the IFIXIT guide: MacBook Pro 15" Unibody Mid 2009 Upper Case Replacement and follow this YouTube: MacBook Unibody Keyboard Replacement.