I recently acquired this radio (for free!) and it looks to be in good shape. It has been sitting idle for some time and most likely the lithium battery needs replacement. Is that something I can do or should it be sent to a service tech?

Ok, thanks!

I would send it into the Futaba USA Service. But call them first. The 9Z is an oldie but a goodie, but I would not fly it until it is looked over.
Call the service center first as it may no longer be serviced by them.

If they will not service it call Radio South, they should be able to do it. But FutabaUSA would be my first choice.

https://futabausa.com/repairs/

Ok, thanks!