I'm a tester for my company and I use a number of browsers to test our product. IE9 is a problem because the password is sometimes remembered, and sometimes not. It is remembered if I need to re-authenticate after 20 minutes of non-use, but if the session ends from 480 minutes of non-use, or I "log out" and open in another tab, the password is forgotten.
That might be a vital piece of info -- if I log out and log back in the same tab, it works, but if I log out and log in to a new tab, I'm out of the game.
The sad thing about this is that the "website" is localhost. I do not use IE9 for anything else. Meanwhile, this behavior doesn't make me want to use IE9 at all.
Sorry, I just dbl-checked and kicked myself. This isn't RTM as I thought. I updated it and will check it out. So far, though, the behavior seems different.