I disagree with avanti1960. I have an RP-7 and I find it to be very detailed, dead quiet, great imaging and spaciousness, but lacking in tube warmth. I called Nick at Rogue and had a very frank discussion with him asking directly about if I should upgrade to the RP-9 as it has the same 6h30 tubes that are found in ARC gear. He told me that the RP-9 is even cleaner and more accurate than the 7. He added that with the 9 tube rolling is nearly impossible as there aren't many (barely any) alternates to the stock tubes. I've since put a pair of BugleBoys in my 7 and it's giving me a bit of that tube warmth. I've got a pair of mullards on order to see if I like those better. Having said all that, my feeling is stick with the 7 if you want options. If you want the greatest detail and accuracy go with the 9.
Separately, I run mine with rogue M180s into vandersteen Quatros and my volume when listening to vinyl is often in the 140 out of 200. The unit is dead quiet though so it's not problematic at all.