There are no Cat 8's on deck 2--only 9's 10's and 12's. The porthole in the Category 9 staterooms on Deck 2 are the big portholes. The Cateogry 9 staterooms on Deck 1 have the two portholes.
The Category 8's on Decks 5, 6 and 7, are the same size and layout as the Category 9's on Deck 1 and 2. You are paying the extra money for the Category 8 because of the location on the ship (higher deck).
You will love your Category 9 on Deck 2. I sailed in one in September of 2001 and really enjoyed it.
Vicki