Any comments on Jeff Rowland Design Model 9

I own the Eidolon Diamond (moved up from the Eidolon last year). The Eidolon Diamond, Eidolon and Radian/HC all seem to have the same loading characteristics according to Avalon's website (4 ohms nominal impedence, 3.6 ohms minimum; not sure of rated sensitivities). My power amplifier is the 50 wpc Accuphase A-50V (which I also used previously with the Eidolon). I can't imagine that the Model 8 in all its versions would not have enough drive for your Radian HC's. I am not sure of the current capabilities of any of these fine amplifiers.

"I gathered that the Radian needs a powerful amp and I think the 8Ti may not be up to the job. "
A priori, that's nuts. The 8ti has plenty of power for any speaker. Are you unhappy with the sound you're getting?

I have owned Radians and Model 8Ti in the past and to me it was more then enough power. Now this is just me. If you want to go for a Model 9 I would call Rowland and ask about upgrades to 9Ti. Can you post why you feel you need more power? What is the size of your room?

extremely extremely transparent sound very strong detailed bass on demonstration upon Dunleavy 6 speakers using same cables and preamp you have. Didn't sound slow at all to me.