The Sun is about brighter than a full Moon from Pluto. But hypothetically our Sun would appear as a super bright star from within the Solar System. Comets and the other planets would not be visible to human eyes. Though its slow 248 year movement across the sky would make it not fit in as a constellation.

But as you push deeper out while still part of the solar system that movement would become less and less obvious.

This is theoretical and does not answer your question directly but from a theoretical planet in the outer solarsystem then yes the Sun would be part of constellation to any civilisation only lasting a couple of hundred years.