Good folks at Sammobile have released Android 4.0.4 ICS firmware for the Samsung Galaxy Tab 8.9 tablet. To flash it, you must have stock CWM on board. The best way to have that is by flashing an official firmware for the Galaxy Tab 8.9 which will restore stock CWM.
You can find rest of the instructions including download links from this thread at XDA. The ROM is for folks based on Austria but would work for any P7300, that is Tab 8.9.