Samsung officially announced the Galaxy Tab 8.9 yesterday, and today, the kernel source has been released. Considering we already know what the Tegra 2 is capable of and how much it can be overclocked while remaining completely stable, I expect to see 1.4GHz kernels pop up before the device is even released.
The source is out for both the Wi-Fi and LTE variants, so if you're into tinkerin', hit the respective links below to download.
Samsung Galaxy Tab 8.9 Wi-Fi Source Code