On Wednesday Sept. 9, Apple CEO Tim Cook took to the stage to introduce the new iPhone 6s and iPhone 6s Plus. But we all knew that would happen. It's what no one knew, for sure, before the event that's exciting.

Apple showed a return to form by successfully keeping several big announcements under wraps, or at least keeping any leaked details vague enough that no one was absolutely certain what they were going to experience going into the big September Apple Event this year. Here's what Apple surprised everyone with.

iPad Pro

It turned out that the iPhone 6s and iPhone 6s Plus were not the stars of the September 2015 Apple Event by any stretch of the imagination. Front and center was the new iPad Pro, a 12.9-inch monster tablet.

Yes, this wasn't one of those out-of-the-blue announcements, simply because the "iPad Pro" happened to be a device that's been rumored -- and before that, dreamed about by fans and bloggers -- for several years. But it wasn't until right before the event that clear evidence (a retail price point leaked minutes before the "Event" began) pointed to the long-awaited, never-quite-sure-if-it-was real iPad Pro.

Perhaps it's because the device was the subject of so many rumors that Apple managed to pull a fast one.

The iPad Pro packs a 5.6 million pixel display, a blazing fast "desktop class" A9X chip that purportedly outpaces 80 percent of the ultra-portable laptops shipped in the last year, and several great accessories that, even more so, took everyone by surprise

Apple Pencil

This, or some kind of Apple "stylus," has been rumored about for a few months and made it into the rumor mill more recently, days before the event.

But the full details about variable pressure sensitivity, a physical brush-style tip that offers fluid changes of line density (think: calligraphy on your iPad), and the built-in lighting connector that can charge the Pencil directly from the iPad Pro were pleasantly shocking -- especially all combined into an attractive thin wand.

Perhaps part of the surprise here stems from the fact that Steve Jobs legendarily hated those devices, once saying, "Who needs a stylus? Yuck! Nobody wants a stylus." If nothing else, this signals that Cook now isn't afraid to take Apple in directions that Jobs would have harshly disapproved of.

tvOS

Apple was definitely going to unveil a new, updated Apple TV box. We knew it would come with a dedicated app store. But the majority of rumor reports missed that it would come with a dedicated operating system as well.

Called "tvOS," this surprise isn't the most ground-shaking, since it looks mostly like a fork of iOS for the biggest screen in your house. But it did catch people unprepared.

Friendly with Microsoft (Office)

After spending years waiting for Office to come to the iPad, it feels funny seeing Microsoft's Office chief up on Apple's stage talking about a custom-built version of the flagship productivity software that's available on day one when the iPad Pro goes on sale.

That has a lot to do with shifts over at Microsoft, but Apple has clearly gotten more friendly with its former rival as well, for example offering the Event's live stream on Safari for OS X and iOS as usual, but also including support for Windows 10's Edge browser for the first time.

Of course, Apple and Microsoft came together over Office compatibility before, in 1997. But when the Microsoft representative took the stage, there were no hisses and boos from the crowd this time (jump to 30 minutes in).

iPhone Upgrade Program

Ever since the wireless industry started moving away from the two-year contract -- and the heavy subsidies that those included, making a $600 device only cost $200 -- questions over the future of the iPhone in the unsubsidized market have been raised.

They were answered, and then some, by Apple on Wednesday with the carrier-agnostic iPhone Upgrade Program.

The new program lets customers trade in their current iPhone and get the latest flagship every year -- unlocked and ready to run on Verizon, AT&T, or whatever carrier you choose. It starts at about $33 per month (for the 16GB iPhone 6s).

To sweeten the deal, Apple includes an AppleCare+ extended warranty for when you inevitably shatter the screen.