Pluto and Neptune orbits are not in the same plane.
Jason asks: "Since Pluto's orbit intersects Neptune's orbit, will Pluto ever crash into Neptune or become one of Neptune's moons?"
Answer: No. From 1979 to 1999, Pluto was the eighth planet from the sun. In 1999, it slipped beyond Neptune to become the ninth. But Pluto's 248-year orbit around the sun takes it 17 degrees above and below the plane in which Neptune and the other planets travel. So their paths don't actually cross as they swap positions. Imagine you are the sun in the middle of your back yard. The fence is Neptune's orbit. You toss a boomerang way out over the neighbor's houses and it comes back, being on both sides of your fence during its travels without hitting the fence. Of course, activity like that can be frowned upon, and in Pluto's case helped lead to its demotion.