score:3
No. This is too short for SE to accept but no. I am not even sure what your problem is: you are flying domestic so you won't be met with border control and also you are admitted 'till October and you are flying in September.
Upvote:2
When you take a domestic flight, there is no passport control at all. There will only be a security check where they check you have a valid ticket (and they will need your passport), but they don't care about the stamps or how long you stayed.
It is only when entering the US from another country that there will be real passport control, with your passport getting stamped