microchip - not a lot to add to the great comments made already, but let me add my regretful welcome. Sorry you need to here, but glad you found us!
There are quite a few of us high-risk types here, most doing pretty well. I'm a G9 5+4 case myself, and have been at this for going on 5 years now. My PSA after all the treatments has apparently leveled off, and with luck we may get years of durable remission.
You are in for a fight, but there are lots of weapons available to you. This forum really helped me out early on, helping me to ask the right questions and providing a sanity check for what I was being told. It really helped my confidence with the doctors, and gave me a badly needed sense of some control.
We have a thread here for G9 & G10 folks, as a gathering place for those of us facing that diagnosis. There are links to the first posts for many of us there too. Our concerns are usually centered on the best aggressive treatments available. You'll probably have multiple treatments, some simultaneously, to fight this thing on multiple fronts.
Here's a link to the thread. I've added you to the roster on the top of that thread, the 3rd in a series:
The Gleason 9 (and 10) Crew - Welcome and how ya doin'? (Part 3, continued thread)