Hi briarfoxinwa,
Since you're flying in the night before I would relax, especially after reading mcnuss's post. It sounds like the airlines did pretty well by you. And they probably have till about 4 pm on sailing day to get the bags to the port if there was a problem.
Definintely, definitely pack your important stuff in a carry on. I would also suggest your change of closes, shorts etc, bathing suits and if you have enough room in a carry on, clothes for the first night's dinner. Also pack your medications, bathroom stuff, anything you wouldn't want to go through a day with out.
The first reason is that your checked luggage doesn't arrive at your stateroom as soon as you do. On our 7 day trip last year, all the bags arrive pretty early, but they don't have to be at your state room until 6 pm. So if your coming in from a colder climate, you'll want a change of clothes and if the pools are a big draw, bathing suits.
The second reason is if your bags get misrouted, you'll have stuff to fall back on until they get there. We did have one experience like this, and now I make sure we carry on what we need. Our first cruise was a 4 day combined with 4 days in WDW. The WDW resort we stayed in on the first leg of the trip never took our bags out of the hotel room. The plan is that you tag your luggage and they take it away and send it to the ship.
There are five of us, and we packed no extras since we were just going from the hotel to the ship. However, and this is one of my favorite Disney stories. About 15 mins before the ship left the dock, guest services called us. They informed us of the problem, and since it was their responsibility (we had their transfers) they immiediately sent up 5 kits of personal care items from the gift shop, issued a $500.00 shipboard credit, so we could buy clothes for dinner, swimming, sleeping etc. They had our luggage, all nine pieces air frieghted to nassau. We had our bags by 10 am the next morning. However, one of them was torn. When guest services called to check that we got everything, I let them know about the torn (brand new)suit case. They said no problem, bring it to guest services and we'll have the ship's appolster (sp) look at it. 24 hours later I had our bag bag, looking good as new.
That was what I called Disney Service. What could have been a HUGE problem was handled so well that we consider it a highlight of our first cruise. But it did make me plan for this evenutalty. When we sailed last year, you can bet we carryed on back ups.
So don't worry too much, but do plan.
Bon voyage