HI 969 the top high front speakers are a proccessed mode(PLIIz) on the amp and as far as i am concered it is very good,it really fills the room with sound.
I have used it with and without and defenalty prefer it on.
With my amp i cannot use the surrround back speakers with the front highs,but can use the surround back,so effectly i am useing 7.1 but with the 9.1 amps i am sure that you could use them all,hope this helps.