The 3.9 kernel release was overdue by one week but Torvalds shared that the week set-back with the 3.9-rc8 tagging ended up being fine and a few small issues were addressed in this time.
The official Linux 3.9 kernel release announcement can be read on the Linux kernel mailing list.
For those who haven't been keeping up on the 3.9 kernel development, highlights are noted within Interesting Features, Changes In The Linux 3.9 Kernel and Top Features For The Linux 3.9 Kernel. Overall, there's a lot of good stuff to this new kernel release with the new additions spanning all major sub-systems. For the Phoronix focus, there's of course improvements to the open-source DRM graphics drivers, file-systems, power management, and performance.