>>720102440
Kind of, but not perfectly. All of the planets, which is to say all of the large bodies in the Solar System, orbit within about 5 degrees of the common center of mass rotation (this is dominated by Jupiter, which is more massive than everything else around the Sun combined). This center of rotation is different than the ecliptic, which is the plane of the orbit the Earth takes around the Sun, and the Sun's own equator/axis of rotation. It's also highly inclined from the galactic plane, the Sun (and the Solar System with it) is tilted about 60 degrees from its path around the galaxy.

>>720102638
The planets and everything else in the Solar System formed from the same disk of mass around the Sun. Most mass was grouped along the axis of rotation and clumped into the planets after millions of years of collisions and accretion. The billions and billions of small pieces of scattered debris left over from this process are the asteroids and comets that have been scattered from the disk by collisions and interactions with a planet's gravity over the billions of years since then.
As an example, even though Pluto is the tenth largest mass in orbit around the Sun (that we know of), it's no longer considered a planet because it was scattered and locked in an orbital resonance with Neptune. Neptune's gravity dominates the outer Solar System and has scattered many objects like Pluto into eccentric orbits. Because Pluto is dominated by another object's gravity, it's not a planet.