Welcome aboard, Roxie! It sounds like you're planning an exciting cruise with Captain Mickey Mouse! Your kids are at such great ages to enjoy all the magic that awaits them on the high seas with Disney Cruise Line!
Since you'll be sailing a closed loop from the United States, leaving and returning to Miami, guests are not required to have passports to sail, however it is highly recommended. If your children don't have passports, they will need a copy or the original of their state-issued birth certificate since they are under 16 years old and traveling with their parents. Adults without a passport are required to show a government issued photo I.D. along with the original or copy of their state-issued birth certificate. You can read all of the specific details about
required travel documents for the Bahamian sailings on the Disney Cruise Line website.
If at all possible, it is a good idea to get passports for everyone in the family. My family likes to travel with our passports, as it gives us peace of mind to know that in the unlikely event that we encounter an emergency in a foreign port of call, we can more easily get back home.
I hope those details help as you continue planning your cruise. Stop back again if you have other questions before you set sail, Roxie! I'm happy to help!