Someone compiled a list of the top spots by month. Here is Sept-Oct
September
Adicora- Venezuela, El Gouna-Egypt, Tucus-Brazil, Mauritius, Pirlanta-Turkey, Zanzibar-Tanzania, Seychelles*, solomon Islands, Rangiroa-F.polynesia, Sumbawa-indonesia, Maui-USA, Madagascar, UK, Corsica, rosslare-Ireland, Canada, Germany, Israel, Sinai, Noordwijk ann Zee-Netherlands, Puclaro-Chile, Mancora-Peru, , NE Brazil
October
Tucus-Brazil, Western Oz, Sumbawa-indonesia, Madagascar, New Caledonia, Chile, Watergate-UK, Esbjerg-Denmark, rosslare-Ireland, Buenos aires-Argentina, Carmelo-Uruguay, Noordwijk ann Zee-Netherlands, Cape Hatteras-USA, Tarifa, Puclaro-Chile, Mancora-Peru, , NE Brazil
You've got a couple of choices there.
I was in your position not too long ago. I booked a trip to Mexico for some more lessons and practice. The best thing I did was buy my gear (only one kite) before I went so I could practice on my own without the high cost of lessons. Most places won't rent you gear if you can't stay upwind, and then the rental is ~$100 per day. If you can swing it, buying gear before you go will save you a lot of money on lessons you could be spending on another kite!