Cat 9 and cat 8 are identical staterooms....each offer a large, 48 inch porthole window....
The sole difference between the 2 is cat 8's are located fwd on decks 5,6, and 7,and cat 9's are located on deck1, and mostly on deck 2 throughout....
IMHO, save a little $ and book a cat 9, deck 2 aft.....better loc than the cat 8's on ship....