I've had mixed results on my last few flights. Most have been turned off when boarding the plane, and like everyone else, I just ask nicely when we board, or when the FA's are walking through the cabin.
Another thing I do is make a comment about Ch9 on ualsurvey.com after the flights. Don't know if that helps or not, but at least I feel like I'm telling someone about Ch 9 awareness.
Too bad Ch 9 can't be like the other channels where its just on all the time with no real control over it.
Do the rest of you feel like you are the only ones asking for Ch9 at all? Sometimes I'll wait to see if someone else asks before asking the FA's. I've gotten some strange looks from the FA's at times.