Is your cruise a 3 day cruise or 7? If it's the longer one, I would splurge on a better room if you can afford it. On the three day trip you don't spend a lot of time in your room because you don't have all those days at seas. Instead you are more rushed to get everything done in a short amount of time. Many of the cat. 9 rooms are also on the first floor but some are on the second. I believe that the ones on the first floor have two very small portholes rather than the one extra large porthole that you will find in all the cat 8's. Do you know how many rooms are still available? If there are quite a few, you will probably be ok to wait until you get to port to upgrade to hopefully get the best deal. If the ship is almost full, I would upgrade now to ensure you get the category you REALLY want! It might cost you more but at least you will be happy with what you get!
JMO
Ann