Honestly I doubt it, I think if we were going to see a V9 it'd be out by now. We're just under half way through the season with 2 events gone and 3 to go, if they were going to put out V9 then I'm pretty sure they'd want to do it for more than half of a season, which means pre-Raleigh (ie. now). I think if they were going to put out V9 before Raleigh it would have had to be already, they have to give suitable time to adjust to new versions (even though they're not massively different from the last these days) for Pros etc, and I can't see them putting out another version between now and Raleigh (though I could well be wrong on that, I suppose there is time to do so). If they waited until after Raleigh then V9 would be in effect for one regular Pro Circuit event and the Nationals only, which I really can't see them doing. It could happen, but I'm pretty firmly of the opinion that V8 will be the last H3 MLG lineup, kind of a pity we never got to see more stuff tried out if so, hopefully Reach will bring a little more interesting variety.
I doubt there's going to be a v9, but if there is the only map addition is likely to be Hexogen. I don't know the entire story, but I know that Killa KC tested that map more extensively than the others from the V9 testing sessions. So yeah, if you're bored of V8 and want to pretend you're playing V9 play that on the Narrows Flag gametype.
With the official announcement that they will be involving Reach in a few of the events for this season I think its clear Halo 3 MLG has developed as far as its going to. I just don't see V9 showing up.
True. I'm pumped as hell for Reach though. They even confirmed streaming for it, though I doubt there will be announcers with Halo 3 still going on.