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. It was originally announced that 1.9 snapshots will begin being published in January of 2015,[2] but this may no longer be the case.[3]
MC-14525 – Name tag doesn't work on entities with right click ability.
MC-16204 – New creative GUI showing detailed effects does not show on some potions. Neither to bows.
MC-28479 – Chest interface not closed when chest is blocked from opening.
MC-42841 – Incorrect creative instant health damage value.
MC-52802 – Mob head takes a fraction of a second to change to selected head.
MC-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.
MC-55942 – Nether Wart hitbox is incorrect on multiplayer. (Untested on singleplayer.)
MC-67163 – Damage value for objective stat.mineBlock is missing.
MC-68062 – Boss health bar only visible when looking at boss
MC-75082 – End music will stop every time the ender dragon loads out of view.