Dreksler said:
...deviate from zero degrees relative to the equatorial plane of the object that it is orbiting?
So, to tease this apart a little:
Are you thinking about how
planets might have aligned in the plane of their parent
star? Or are you thinking more about how
moons might have aligned in the rotational planes of their parent
planet? (not to mention comets and asteroids).
Because I think there's some nuances in how the initial conditions evolve to the observed conditions.
Example:
Planets evolve from a vaguely spherical, rotating gaseous cloud of a proto-solar system on a broadly similar timeline as the sun itself coalesces.
But
moons are not necessarily analogous - they do not likewise evolve from a vaguely rotating spherical gaseous cloud of a proto-planetoid, coalescing at the same time.
There's a lot of moons that get their orbits long after their parent planets have coalesced. Some captures, some impact ejections, etc. These have no analogue for planets.
Apples and oranges, you see.