I've spoken to Apple support again.
the re-install doesn't work
Logging out and logging back in doesn't work.
Logging out and in to another GC account doesn't work.
I logged in to my GC account from another pre IOS 9 phone and that worked.
Adding all this together shows that the issue is not with my GC account but in fact it is to do with the install of IOS 9 on my phone.
I have a call back set up with a senior Tec from Apple for tomorrow. They said he will go through it more in depth and will try to get some logs from my phone. I will update you with anything they find.