Need some info about iPhone preordering?

Ok so I love the new iPhone 6, I want to get the unlocked $649 model on launch day but I have never purchased an iPhone on launch day before and I assume there will be lines and the store could end up being sold out by the time I get there. The store is about an hour drive for me so I would hate to waste all that gas just to be told the phone is sold out when I get there. I was wondering if Apple will let users preorder the phone for pickup on launch day? I know they are going to start preordering on the 12th but will I be able to preorder FOR IN STORE PICKUP? Also, will September 16th be too late to preorder, this is when I get paid and I won't be able to preorder till the 16th.

Added (1). I will be going to the Tampa Apple store in Florida.

I don't understand why anyone needs to get a phone the first day it comes out. Just wait a week and there will be no lines and plenty of stock in stores.