There is no "best" when it comes to a 9 channel amp. Just too many channels and power demand to do it right.
The Monolith is made by ATI Amplifiers in the US, and would be the best option for pure power. Emotiva does make a decent amp too. If I was the OP I’d use an upper end AVR as the pre, and have the following configuration: AVR running the atmos speakers, with an amp driving the 5 channels. Run the AVR’s room correction and you’re all set.
For a 5 or even 7 channel amp there are lots of options. I’d go with either Outlaw Audio, Adcom or Emotiva. All are buy online. The Adcom only has the one model 5 channel, at 200 wpc and almost 100 pounds, so that might be overkill depending on the speakers being used.
The Monolith is made by ATI Amplifiers in the US, and would be the best option for pure power. Emotiva does make a decent amp too. If I was the OP I’d use an upper end AVR as the pre, and have the following configuration: AVR running the atmos speakers, with an amp driving the 5 channels. Run the AVR’s room correction and you’re all set.
For a 5 or even 7 channel amp there are lots of options. I’d go with either Outlaw Audio, Adcom or Emotiva. All are buy online. The Adcom only has the one model 5 channel, at 200 wpc and almost 100 pounds, so that might be overkill depending on the speakers being used.