We are sailing the Carnival Pride 11/30/03.
This is our 7th Carnival Cruise!
We have never checked in early. We usually book our own air and arrive one or two days early.
We will go to the cruise terminal early on Sunday- by 10:30 or 11:00 or so. Luggage is checked through and will show up in your stateroom.
We always get an outside cabin with balcony, and they do come with robes. I don't think the cabins on the inside or without balcony get them. You can buy them tho!!!

Personally, I would never wear jeans to dinner in the dining room. Jeans are OK for breakfast or lunch, but not in the evening. Hawaiian shirt is probably OK with dockers....
We always have enough room for storage under the beds and we have a ton of luggage!
I hope this helps and have a wonderful vacation!