I am running my pair of RS9 Kappa(originals) with a pair of McIntosh MC2600 left in stereo hooked up vertical bi-amp which are capable of 600rms/2200peak w/102.5amps peak current from each of the 4 channels driven by a Carver C19 Reference vacuum tube pre-amp(rolled to E88CC 5-gold pin black plates). It was sad to see all those people turn you off because they were mostly wrong. They're not that terribly hard to run, BUT, everyone "was" correct in stating that you'll never hear what they actually sound like until you throw enough power(current) at them. I think you made the right move perhaps. I don't think there are many who would really want to go down this road. The K9's will absorb "both" MC2600 into power guard at run and hide volumes and sound absolutely incredible(from outside) but also at any level below that even down to a wisper and you can still feel the bass a little in your chair.
If they're still in storage and you want to entertain yourself, find a pair of old Hafler XL600 amps for cheap(I've had them). They will run your Kappa 9 very well. Beautiful warm detailed(tube) sounding mosfets with the muscle. Get them recapped, maybe buy a couple of the cheapest sets of upgrade boards from Musical Concepts or Van Alstine,
vertically bi-amp them and you will be completely amazed with what you had in your closet. Anyway, I'm sure they're gone. Would be fun though. 😁