Board Thread:Naruto Novel Discussons/@comment-25319479-20150725151541/@comment-3279282-20150728191741

I'm saying they aren't canon because they're an adaption of the official material. According to wikipedia, "In fiction, canon is the material accepted as officially part of the story in an individual universe of that story.". The novels have never appeared as part of the story (= the manga), hence they are not canon. A good example as to something that became canon despite being initially published in an adaption is Raiga Kurosuki.

Oh and there was also a timeline released that excluded the novels and only listed the manga chapters, The Last, Gaiden and Boruto The Movie.