iOS 9 Release Time
Apple hasn't announced an iOS 9 release time and there's a good chance that it won't.
If you want to download the iOS 9 update right when it comes out, do not show up tonight at midnight PDT. There probably won't be anything to download.
Instead, you'll want to plan Wednesday around a potential 9AM-10AM iOS 9 release time. This is generally when Apple releases its iOS updates. Here's how that looks in other parts of the United States:
Eastern – 12-1 PM
Central – 12-1 PM
Mountain – 11AM-12PM
And here's how it looks in big international regions: