We use cloth diapers on my DD (18 months) except at bedtime. I've been contemplating bringing them with us in June, but we are staying at Pop and I just don't want to spend part of my vacation tending to diaper laundry...so sposies it is! If I were staying at at villa with W/D I would be taking our CDs for sure. Here are a few thoughts:
1. You could use a hybrid system like Flips, Grovia, gDiapers with sposie inserts. I haven't used sposie inserts myself, but when I researched the topic I found that a lot of mamas like Flip covers, but not the inserts so they recommended using gDiaper of Grovia inserts in the Flips covers.
2. Your son may not be going through as many diapers by the time you go in September or October. My DD has started to hold it and then flood the gates so to speak, so I'm finding that we aren't using as many diapers in day now.
3. Will you be going back to the villa for a midday break/nap? If so, then you won't have to carry around a huge amount of diapers at once. You'll be able to reload the bag when you go back to the villa.