IE9 was just introduced as an upcoming feature for Windows Phone, presumably in the 'Mango' update. While some of it was discussed during Ballmer's keynote, the nitty-gritty was given to Marini, who gave an excellent talk on all things IE9 and IE9 for Windows Phone.
The question about Adobe Flash was of course asked and so far, it doesn't sound like anything is close to being released:
So the questions is, are we going to support Flash in IE9 for Windows Phone
We are working with Adobe, but it has not yet been decided the last time I checked--part of that is Adobe is doing what they have to do and we're doing what we have to do. The last I checked the team is working with them but I don't think they have any announcement whether it's going to definitely work or not.
We also asked Marini about updating IE9 independently of the OS--something that was mentioned nearly a year ago, specifically does this feature exist/will Microsoft be using it? The good news is that the feature is still there:
One of the great things of Windows Phone 7 is we now have the ability to push out updates independently of the OS. We haven't announced what that schedule is going to be, but as we get closer to the release date they'll have more to say about that, but we're paying very close attention as to the best way to do that