The planets rotate as an after effect of their creation, the dust clouds that compressed span as they did so and the inertia has kept it rotating ever since.
It's fairly easy to prove that planetary bodies are rotating just by watching their features move across their respective horizons.
This seems less easy to discern for amateur astronomers in the case of the sun though.
Does the Sun also rotate as a by-product of it's creation? What evidence is there to support this? Does the sun have any discerning features that make it evident it is rotating?