This is a common confusion, 12:00AM is technically midnight. So you had until midnight on Sat the 9th of September (according to PST/PDT). If he had stated 12:00PM then that would have been midday. From the beginning they stated that you have until 9.9.17
That's written in the original post.
So as long as you submitted by 9.9.17 (according to PST/PDT) you should be fine.