Today my Xperia Premium updated to 9, and my mobile data is not working properly. It says no internet or says lte, but either way won't open anything, except messenger. All the other apps, including chrome, have no access to internet.
I had the same issue with android oreo update. Nothing helped me except updating phone again with my pc and sony application and i ve lost there all the data. It seems like an issue with your operatkr not being compatibile with the update. Try restarting the phone.