Jeanne, doing it the way you are on Sept. 10th is early and more than on time in my opinion (as long as enough tax was paid in by April 15th so there will be no interest and penalties, of course).
But some clients routinely seem to like doing the info-gathering as late as possible and as quickly as possible, get it to the tax office on Oct. 5 or even later. Yes, they spend less time on it that way, but they almost always miss things that we have to get back to them on while preparing, and I don't think it works out well for either the client or the CPA.