I've never seen or heard anything about a curfew on Aruba. It's not looking like they do. After all, it's a vacation spot. I'm guessing there isn't one.
yes, there is a curfew on aruba: if you are under the age of four you can't drink in bars past 2a.m., and if you are school age you cannot be in a casino past 5 a.m...of course, this curfew is waived for pre-schoolers and they may gamble 24/7 since they technically aren't in school yet