The "will they, won't they" saga with the notorious case of the disappearing in-display fingerprint reader seems poised to continue, as Samsung has recently been granted a patent for such a contraption, building on the notch-y scanner patent we saw not long ago. Not that we will see the under-glass thingy in time for the Galaxy S9, as Samsung's marketing manager is on record tweeting that the "tech probably won't be ready for retail by then."
That could leave it for the Galaxy Note 9, but in any case it is a device with Infinity Display design that we are seeing depicted here in the Korean patent database filing. It's tough to master the speed and accuracy of a touch scanner when you have just an emitting component hidden under a cover glass and screen package to rely on, as both Samsung and Apple failed to perfect the technology on time to include it in the Galaxy S8 or the iPhone X, while Apple even went with an entirely different biometric solution.
Still, we are having the first devices with in-display finger scanner being teased for next year, so we wouldn't be surprised if Samsung ditches that elliptical thingy by its cameras when next fall rolls in. Moreover, in its newest patent grant, Samsung couples the reader with a pressure sensor, so nothing in the current design would have to change at the front. Samsung is still rumored to use the same 6.32" panel for the Note 9 next year, so we might only see a more refined Infinity Display design, while most of the other changes could be reserved for under the hood.