Similar issue on my 96 legacy.  Some mechanic had mostly stripped the hole in the bracket that the pulley bolts into (but left it as is) and had also stripped the left side tensioner bolt hole - and solved that one by drilling out the tensioner and running in a short 3/8 self-tapping bolt.

I had to mill out the oval slot in the new tensioner to fit the 3/8 bolt, tap the bracket for a full-depth 3/8-16 thread, and helicoil the pulley bolt hole (lucky to have 10 x 1.25 helicoils on hand).  All went together OK - with a bright orange note nearby about the 3/8 bolt ;-).

new bracket installed, timing job finished up (including seals, idler pulleys, water pump & new t-stat), coolant conditioner added to fresh coolant, and it even got an oil change today.

She is up and running like a top!

Quite happy right now.

 

Now I just need to swap over my good tires from the Legacy (already on the Forester rims, hehe) and probably my bluetooth/usb/AM/FM/CD stereo as well, get some seat covers installed to protect the near spotless upholstery (already ordered), and a few other odds & ends to make it mine...and fix the few minor rust spots and we should be good for many years to come.

 

Thanks to all that helped out.