Yes, it is true. Lava lakes has been added to the 1.9 update/snapshot (Still buggy) And some potion stuff idek what is for. I did take other screenshots of bugs and awesome stuff about 1.9 but the screenshot files was too big. ;-; This is not world edited. Go and try it yourself.
Lava lakes were a thing since Alpha 1.2.6... The potion stuff is lingering potions which leave a cloud of particles when thrown that will give any entity that walks into it a specific status effect.
You used the customized world generation, which was since 1.8. If you didn't, it's a glitch because it's not mentioned anywhere.