I am curious about this too. I have a 5090 (reserved) and previously bought a VESA compliant tilting wall bracket (32-63", 70kg max) but I have been totally stumped with finding out if the 5090 is simply VESA compliant.......
Didn't your TV come supplied with the wall bracket? My Pioneer came supplied with the bracket so I'm assuming that it is from Pioneer. Try going back to your dealer and ask for it.
I think any wall bracket would do unless you want something fancy that can tilt/swivel by 180 degrees, etc.