One thing you definitely want to do is buy an Annual Pass on your June trip. You will get many discounts with the card in addition to it being less expensive for park admission on your two trips than buying park passes each time. Discounts include lodging, dining, shopping, recreation & more. I would advise going ahead and booking your September vacation to make sure you get the resort of your choice, but once you check-in in June you may find a “bounce back” booking offer in your room. You have to act on this while you are on your Disney Vacation–after you check out you are out of luck. SImply call the number on the card (or in a booklet) and ask if your existing reservation can be updated with this discount. Or, if you book through a Disney Travel Planner, contact your agent and he or she can take care of it while you enjoy your vacation. You may have to change room categories or even resorts to get the discount. There may not be a bounce back offer on your vacation, but usually at least an Annual Pass discount will be released that you can apply to your room in September.