No, you don't have to wait until they fall. I usually rack off of the dryhopping in 3-10 days, depending my my schedule.
You can stick your racking cane into the middle of the beer, under the top layer of hops debris, and above the trub layer on the bottom. As the beer lowers, lower the racking cane. That works well to keep the hops sludge out of the bottling bucket.