Given that the Note 9 hasn't seen a US beta release yet, I'm not surprised, as that came out a week earlier than the S9 in other regions. Though they may skip the beta given the success of the S10 update, as the full version has already started rolling out to users in Germany.
Considering that the official update is rolling out to the S10s right now, I have my doubts that we'll see a beta for the S9 and S9+. I know folks are saying that there will be a beta, but with a roll out date of January/February (depending on the source you read it from), that's not a lot of time for actual beta testing.
I remember having to wait a few months to get the original stable one u.i update that started beta testing somewhere around September or October of 2018 I do believe but still Samsung is ridiculously slow at pushing updates especially when they're not actual interface updates do who knows lol word is we might be getting the beta sometime this week but that's all just speculation and also I'm kind of upset because I shouldn't have to be pushed to the back of the line for not going out and buying a brand new device