Hi Hawaii,
Yeh mate Port should be OK September, wind generally 12 to 20 if the weather's clear but this year has been fairly ordinary so far, leave your wetsuit home. There is a great kite camp run north of Cooktown, do it guaranteed fun.
The old is Yorkey's / Port Douglas windy in the month of (insert) question has been done to death in your own forum

Cheers Bob.