Question

What is the nineth plant closet to the sun

Answer 1

Well, since Pluto's demotion, the solar system only has
eight (8) official planets, so there's no official answer to
your question.

To some dinosaurs like me, when we talk about the solar system
without Pluto, it always feels as though something important is missing. 
If you still hold on to Pluto, and still consider it to be a planet no matter
what those who know what they're talking about are saying, then Pluto
is your ninth planet closest to the Sun.

Answer 2

My Very Excellent Mother Just Served Us Nachos 
(or Nine pickles if Pluto was a planet)

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
(Pluto)

hope that helped