1.9 is an upcoming update to Minecraft with no set release date, currently only listed in the bug tracker as "Far Future Version - 1.9+"[1], as well as mentioned by the Minecraft Developers.
14525 - name tag doesn't work on entities with right click ability
16204 - New creative gui showing detailed effects does not show on some potions. Neither to bows.
28479 - Chest interface not closed when chest is blocked from opening
42841 - Incorrect Creative Instant Health Damage value
52802 - Mob head takes a fraction of a second to change to selected head
54486 - Glass panes and iron bars don't connect to graphically opaque blocks that are registered as transparent. e.g. slime blocks, ender portal frame blocks and monster spawner blocks.
55942 - Nether Wart hitbox is incorrect on multiplayer (untested on singleplayer)
67163 - Damage Value for objective stat.mineBlock is missing