I read Samsung released it for some Exynos versions of the S9. Have not seen anything for Snapdragon variants. Don't hold your breath. Project Treble is probably Project Terrible for Samsung Snapdragon owners.
I got it on my S9 Plus last week (SM-G9650, Snapdragon 845).
It has been in Samsung 's hands for a month. Any rumors about date when it eillc$e to us?