Apple recently released Xcode 9, which ships with a Swift 3.2/4 compiler. Swift 3.2 includes numerous features (such as support for where constraints on associated types), while still being a member of the Swift 3 family. So, my question is:
Is Swift 3.2 production ready? Can I write and deploy apps to the App Store using Xcode 9 beta?
You currently cannot deploy to the App Store, it will take some time and upcoming Xcode betas until that's possible. In the last years we didn't need the GM to upload to the App Store, but the first Xcode Betas didn't let you do that.