It is canon. Many of the elements of the show came directly from George Lucas. His word is like the Word of God in the Star Wars universe. Sure, there are points that I don't like, but I have to accept it as a fan.
I posted this picture to my fan page not long ago with this quote
“I must not fear. Fear is the mind-killer. Fear is the little-death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the fear has gone there will be nothing. Only I will remain.” ― Frank Herbert
I'm surprised no one said it before :'> I think also must say: I'm in love with your work since I first encountered it somewhere in the DnD rulebooks. I'm happy to see that artists of such level are found here, on dA.