I flew Van's 9A but have never flown any other RV--so take this with a grain of salt.
Most of my time is flown in a Cessna 182. The 9A, on my short flight, seemed every bit as stable as the 182 (at least on a calm day), but much more responsive--it went exactly where I pointed it, right away! Gus at Van's took me on a flight, banked about 25-30 degrees, stalled three or four times, and the wings did not even drop an inch--the plane just mushed in that same 25-30 degree bank. Stalls in C150s while I was training were not nearly so benign--they always dropped a wing on me pretty hard. One other thing--Gus gave me the entire approach, from the practice area, into the pattern and then over the fence. I kept expecting him to take back the controls and finally, did only to keep the nose up on roll out. It was a very easy plane to fly. I learned in about .5 hours!
Perhaps more important, from my perspective... I chose the 9 over the 7 for the much lower stall speed and sink rate over the 6/7/8. If you have to land off airport, a stall speed of 44 vs 51 mph or whatever the differences are (it's about 7 mph if I remember correctly) mean an exponential increase in survivability if you hit something. Just as importantly, the power off sink rate is about 700 fpm in the 9 vs about 1500 fpm in the 6/7/8. I'll take twice the amount of time to figure out what I'm going to do when my engine fails any day!
That said, I too will wish I could occassionally go upside down, but choices have to be made. So far I'm completely happy with mine. If you want to go upside down, get the 6. If you have no need to go upside down I cannot see any reason to get anything other than the 9 (except you will probably have to build it yourself until more 9's are flying and being sold)!
Good luck with your decision. I was basically in your shoes a couple years ago.
Steve