Originally FreeBSD 9.0 was supposed to arrive in September, but release delays pushed the final release back to November. Even since that revision to their 9.0 release schedule there's been delays in getting out RC1 (the release this weekend was originally supposed to take place on 7 October). So now we're looking at probably a mid-to-late November release for FreeBSD 9.0 final, but not 3 November as there are still two more release candidates expected.
There's many improvements to FreeBSD 9.0, among which are a new installer, a cpuset API for binding threads to certain CPUs and CPU resource grouping/assignment, support for booting from a GPT-labeled disk using a new "gptboot" boot loader, the aac driver can now handle disk volumes in excess of two terabytes, the ZFS file-system has been upgraded to version 14 with support for NFSv4 ACLs, and many other improvements.
Those interested in FreeBSD 9.0 can find the 9.0-RC1 announcement on the mailing list. Additional details are available from the 9.0 TODO list from release engineering and the tentative 9.0 release notes. Those wishing to dabble with FreeBSD 9.0 in a desktop-friendly and easy-to-use manner, PC-BSD 9.0 RC1 should be available at any time now too.