WordPress is working on some fixes of WordPress 2.9 and released WordPress 2.9.1 beta 1 a few day ago. Now they have released the Release Candidate 1 for WordPress 2.9.1 after some amount of testing.
RC1 is having fixes for some more tickets and that’s why the total number of tickets increased from 17 to 23 in WordPress 2.9.1 Release Candidate 1.
You can download the RC1 and use that on your test systems. The stable version of WordPress 2.9.1 is expected to come in next couple of days.