On our Wonder cruise a few weeks ago we were told to be back on the ship by 9:00 pm sailing at 9:30 from Nassau. The fireworks were not ready yet for the Wonder at this time but I believe they are now (hence they need to leave the port earlier so they can set off the fireworks at sea). Plus the Pirate night is this night at 10:00 with the night buffet starting at 11:00 . Unfortuntely it was raining on our night so everything was moved in doors and basically not worth it as there is not enough room in the atrium for 2,500 people.
Now the departure time might have been advanced since then to give more time for the parties and since we did not have the fireworks yet it could have changed.