The Bees
September
The population of the hive is beginning to decrease; older bees that die off are not replaced in the same numbers by the new brood. Drones are being removed in numbers from the hives by the workers to conserve winter stores. Nectar and pollen sources are becoming more scarce as the cooler weather moves in and plants begin to die off or go dormant.

The worker bees will begin to bring in large amounts of propolis to seal the hive against drafts for the winter and on cold nights they will begin to cluster inside the hive. There may be intense robbing activity if you have a weak hive in your apiary - take steps to equalize colonies or prevent robbing.
Remove all honey supers before the end of month (if not sooner) to allow the bees to fill the brood chambers with the winter honey/pollen stores.

You have a lot to do this month. First, you should be pulling off all honey supers and be either securely storing them or extracting them. This will prevent the bees from wasting nectar/energy filling a super/frames incompletely and allows them to build up their stores for winter survival.