If the car is brand new and delivered in Sept them definitely do it in September. Mileage wise you haven't gone beyond 12,500 miles so your warranty should be valid if you do it after the holiday.
Do you have a service plan? If not, do becareful as they will try to sell you one at the next service. Also check if any wear and tear items need replacing, if so, do it before the service as it can be more expensive at the Honda Dealer.