Yea you will need to flash to a non carrier version of android 8.
If you download Sam firm and put in your device details and location code it will download the correct version for you.
Me too. S9+ from Samsung store on EE network, registered in the Members app in the UK.
No.sign of the download yet will be checking.
Have space on the device and updated all apps.
In theory, yes you should get the update if you have been allowed to register for the programme. In practice though it may not work that way, but with any luck....