The active XDA-developers community is a hodgepodge of expert information and guides to Android modification. Naturally, such a user-driven community will inevitably be home to unconfirmed leaks and interesting tidbits about upcoming Android handsets. One such thread is already claiming to have inside information on the next Galaxy flagship not 4 months following the availability of the Galaxy S8.
According to the source and the author's supposed close ties to the manufacturer, the Galaxy S9 is expected to carry the designation SM-G960 with Android 8.0 Oreo, Experience UI 9.0, and either the Snapdragon 845 or Exynos SoC depending on region. It would also be equipped with the same QHD+ (2960 x 1440) double-sided screen as the current S8. Interestingly, the S9 could launch as early as Q1 or Q2 2018 to coincide with a February reveal at MWC 2018.
The source is not expecting any major design changes from the S8 based on early prototype units of the S9. In particular, the South Korean manufacturer may be having trouble embedding an onscreen fingerprint sensor due to the unique production requirements the feature would entail. Even so, most of the information given is rather generic and expected from any 2018 flagship smartphone including the 64 GB of storage and 4 GB of RAM. While anything can still change from now until the eventual reveal, the Galaxy S9 is looking to be a marginal update to the S8 all things considered.