There's no advantage to applying ridiculously early
versus just early.
So long as you apply before the EA deadline, or,
if there is no EA deadline, November 1st, I don't
think it makes much difference.
They probably won't even look at your app before
November 1st anyway. A lot of the adcomms aren't
even around in early fall -- they're off doing
campus visits.
Just get your stuff together by September, and wait
until the schools say they're accepting applications.
Then go ahead and apply.
I'm not saying you should apply in February or March.
I'm just saying that October is probably just as good
as September.