Whats the difference between Integrated and power amps? Arcam Alpha 9 and 9p??

[STIFA]

I wasnt into the amps very much as I bought Marantz 6300 ,but now I am offered used Arcam Alpha 9p wich is a power amp. I thought amps were all the same ...they amplify...
So whats the difference between power and integrated amp.? (integrated has volume controls on it and my power amp model is almost without buttons)??
Anyone knows this model 9p? Should I buy it (4 yrs. old)?
Can I use power amp with CD player to have hi-fi system?

[spacedeckman]

The 9 has a volume control and input switching, tone controls, and other stuff. The 9p has a power switch, a speaker switch, inputs, and speaker outs.