I am having the same problem and have tried 4 separate devices. The premiership and championship forums never load and general nonsense is hit or miss.
Devices tried are a Motorola phone and Nokia, Lenovo and kindle tablets.
You need to have some form of ID and collect your ticket from the club shop as detailed in the email you received. You won't be sitting in your own seat. At the Celtic game people were entering the ground right up until kick-off. Arriving earlier might mean you have to spend less time queuing for the temperature check etc.