I'm rather late to the party of Upload issues that ensued with the GM release, but I'm also having problems submiting to iTunes Connect.
I'm getting the dreaded "Invalid Toolchain. New apps and app updates must be built with the public (GM) versions of Xcode 6 or later, and iOS 8 SDK or later. Don't submit apps built with beta software." This is a build that got through validation in XCode and the initial upload to iTunes Connect, but it fails immediately on submit.
While I got this while running the XCode 7.1 beta (it caught my use of Beta 1 when I first uploaded for testflight testing), I'm also getting it on the live version of XCode, 7.0.1 (7A1001), running on Yosemite 10.10.5
Inspecting my .ipa more closely, DPPlatform Build and DTSDKBuild are reporting as 13A340, which was the version number for the 9.0 SDK release -- I'd expect a higher version for the 9.0.1 SDK (13A404).
This seems to be a bug in either the validator, or in XCode reporting the wrong SDK version. It seems to be looking up 13A340 and deciding it's supposed to be 0700 rather than 0701, so flags this as a beta.
File radars on bugreport.apple.com and cross your fingers somebody cares.
Meanwhile, I've downloaded Xcode 7.0 from http://developer.apple.com/downloads/ and submitted a build with that.
Direct download link: Xcode_7.dmg