if Kishi wrote the script, work on it or even just approved it, it's canon, nothing more to say.
people are being mean because they don't agree with his choices, sorry i don't understand this kind of logic, Naruto is Kishi's work not ours :|
Not because kishi wrote it means is canon, i think canon means that it follows the events of plot of the manga, for example if in the movie neji and obito never died, that means the movie is contradicting the events of the manga itself, therefore that is not canon, but let´s say in the movie neji and obito did die during the 4th ninja war like in the manga and the movie follows the same events but that may have a different focus that is canon because it´s not contradicting any events of the manga itself, which is the main plotline.
None of dragon ball movies except the last one may be canon, the reason is that the DBZ movies contradict the plot in someway for example the janemba movie, goku was dead, vegeta was dead too, gohan didnt have his awakened powers but trunks and goten knew how to make the fussion technique, fat majinbuu didnt exist, that is not canon because it contradicts the events of the manga and anime itself.