Latest model surround receiver for bose 901 speakers VI
I can think of no reason any amp pushing 120 watts would not work with 901-VI's. They're very efficent and will probably play louder and cleaner than you would ever need. As I recall, my old series IV's have no maximum amplifier rating specified, but I did blow up a bridged Carver M-400 Cube (pushing 400 watts to one speaker with a DVD-Audio of Yes - Fragile cranked dangerously high) with them. I'm convinced my speakers are indestructible in any home application.
Keep in mind that whatever you decide to use as your control/amplifier section, a pair of 901's need a dedicated stereo amplifier. I suspect you're thinking surround sound so a receiver with separable preamp/amp channels, due to the Activbe EQ, would be needed and as far as I know they don't exist. A separate stereo amp for the 901's was my solution. I run a Carver AV-406 (5-channel amp) for my 901's in Front, 2 Subwoofers and the Rear Surround channel, with the Active EQ between the receiver and the 901's amp channels. My receiver controls everything and just drives the Center and Surrounds.
Modest amps would work but at very loud volumes may go into clipping, which is bad for any speaker. 120 clean watts is good. I'm using only 110W for mine.
A Carver M-200 is a fine, efficient amplifier that would have you cooking just fine (2x100W).