The version number of Ubuntu is 9.04 and is based on the year and month of release. So 9.04 means 2009 month 04 (April).

Therefore given that Ubuntu maintains a 6 month release cycle we can postulate:

So the new release 9.10 is due this month (October).

And here's a picture!

From previous experience with Ubuntu releases my advice if you are keen to install it hot of the press is:

Download the Live CD ISO. Burn it and boot the Live CD and test.
If you have plenty of RAM on you box you can install into a Virtual Machine and test from there (VMWare of VBox).
Identify and test critical stuff in a sandbox first... I have caught myself out several times with non-working PPTP clients and buggy rdesktop builds, which caused annoyances when I had to connect back to work.
If you're going to spend alot of time backing up all your data and moving it to a safe place before re-installing. You really don't want to have to roll back to a previous release because you stumble on a show stopper.