Try this:
- Archive a new build, with a new build number
- Find the archive in the organizer > right click > show in Finder
- Right click on the archive > Show package contents
- Navigate to Products > Applications > Right click on your app > Show package contents
- Open Info.plist
- Modify BuildMachineOSBuild to 14F27
- Modify DTPlatformBuild to 13A340
- Save Info.plist
- Submit the archive in Xcode
This will make iTunes Connect think you built your app on Yosemite GM and iOS 9 GM and resolve the Invalid Toolchain error. I'm no longer getting the invalid SDK value error, so I think Apple at least fixed that.
This answer is not mine. It comes from other post:
https://forums.developer.apple.com/thread/23534