Hello Alex8 !
Right now, you cant, because, due to the outage, all previous buid where deleted from the servers and still have to be build again, as soon as the team find time to deal with this workload.
you will have to find
OK, no, the S9 is not a legacy device, so through the smartphone selector you can find this download page
You should read again the manual method. You can find it within the S9 line, in the selector.