Someone at xda forums has made the factory, stock ROM for the Samsung Galaxy Tab 8.9. This ROM has to be flashed by using an application called ODIN and is compatible with the Wi-Fi model only. After flashing, you will be running Android 3.2 honeycomb operating system.
Download the ROM from here. If you do not have the ODIN, you can get it from this xda thread. Make sure you have backed up your data as flashing new ROM will return your Tab to the factory state, meaning everything stored on it will be deleted.