Well, it's still being polished in order to make it as good as possible. One of the things I really want to avoid is a repeat of our Moodle 1.7 release which was (in retrospect) a little rushed - the implementation of Roles caught a lot of people by surprise.
So in the name of stability and clarity and consistency and all those good things, we are having a Moodle Bugathon.
All developers and testers are welcome, even if you've been lurking until now. Join in the bug stomp, and let's make 1.9 the new 1.6.
Full details are here: http://docs.moodle.org/en/Bugathon