Channel 9 is great - its been around for quite a while.
Sometimes "its not working"...so I've been told when I ask to have it turned on...and there's music coming through on the channel instead.
A part of me is led to believe that it "is" working but that the pilot prefers to not have it available. Just a wild assumption...but if that's really the case why not just give that as his/her reason?
And oh...while we're on the United thread, I like the full mileage given to you even on super saver fares when flying domestically (flying YVR/YYZ return getting a half point per mile kinda stinks).