Will Minecraft 1.9 pre-release map seeds be changed in the final version? [closed]
First off, it's not the map seeds that change, it's the terrain generator. And while I don't know for certain, I'll say this: It's very likely.
Each new feature that is generated with the world requires an update to the terrain generator. Counting on the fact that after 1.9, it will never change again… well, it probably will.
Specifically, the 1.9 pre-release introduced some pretty big changes to terrain generation (mostly in the Nether), so it will probably be tweaked for the 1.9 beta.