Traditionally the .9 patch comes right at/around/after the next major point upgrade to the operating system. It being a finish-things-up patch to get as many of the known bugs taken care of as possible and to groom it to play nice with the next OS. If they're putting it into testers' hands now I expect that Steve's claim of Spring of '07 to lean heavily on the early side of that quarter for a Leopard release.
Can't wait! ^_^