Does iOS 9 update require iOS 8.4.1 to be installed first? At work I have 3 devices to experiment with today: An iPhone 5, an iPhone 6, and an iPad mini.

The iPhone 5 had iOS 8.4.1 installed on it. Early this afternoon (US Eastern time zone) iOS 9 showed up on the iPhone 5 as an update.

My iPhone 6 and iPad Mini both have iOS 8.4 on them (Not 8.4.1, 8.4). Software update on both devices offers to update to 8.4.1.

After about an hour of waiting, I decided to try installing 8.4.1 on my iPhone 6. Sure enough, once I was through the install process and actively online, I'm offered an update to iOS 9.0. My iPad mini still shows the next update as iOS 8.4.1, not 9.0.

WTF? These are big, time-consuming updates. It seems silly to have to download and run the full install process for an intermediate step update.

Is this how Apple does over the air updates to iOS 9? I thought Apple bundled updates into a "combined update?" but don't see a way to do hat other than downloading the install image and using iTunes to update over USB.
this problem occurs when you already have a downloaded update (for example, you have downloaded 8.4.1 but not installed it yet).
Easiest way to correct is to delete the update (Settings-General-Usage-Manage Storage - look for iOS8.4.1 (or whatever version has been downloaded).

After deleting the old update, a check for software update will show iOS9