In regards to 1.9, the plugin will not currently work since it relies on NMS modification. Unfortunately the method used to do the modification does not work in 1.9 and I have not worked out a new one yet. Depending on time and complexity of the fix it may be a while and possibly will not be updated at all though I hope it doesn't end up that way.

In the meantime I have created a patch for use with BuildTools that will achieve the same effect as the plugin however it is not world-specific; any world using the vanilla generator will have FarLands. It is considerably simpler though, as most of the plugin actually is just digging into the NMS files so it can make the changes.

https://github.com/OtakuMegane/FarLandsAgain/blob/master/0151-Re-enable-Farlands-for-1.9.patch

To use it all that should be necessary is to drop it in the Spigot/CraftBukkit-Patches/ directory then run BuildTools like normal to compile a new server .jar