XDA devs rock, ain't they? Head here if you are desperately waiting for Icecream Sandwich on your Galaxy Tab 8.9. But do note that Wi-Fi doesn't work yet. Here is a log from XDA:
Hardware Acceleration, Tested angry birds and it works, transitions seem to fly!
GPS works!, a bit slow but since wifi doesn't yet I have no agps data
Green flashing screen (on mine, not poisike)