No, if SM series is canon to XY and older, they would specifically reference Misty and Brock in dialogue from Ash about having traveled with them before specifically to ensure audiences got M20 wasn't canon at all. And besides which, if Rica said those things and the writers didn't approve, whether it dealt with an AU or something else, there would have been severe consequences for her. I know this because the likes of Sophie Reid, Carla Nella, and Rafaelle Cohen actually indicated such was the case if they even divulged the backstory they created for the characters specifically BECAUSE it wasn't officially-sanctioned, not willing to divulge it even when I made clear that I only intended it for a fanfic and would have made note it wasn't actually canon.
And don't forget, this is the first movie to even feature an actual tie-in manga between the movie and the anime, which was unprecented by a significant degree. While the fact that the movie contradicts the original series does suggest it's not canon to it, the fact that a tie-in manga was released tying it and the SM anime together strongly suggests its canon to SM at least (which indirectly implies that SM is not canon to XY or any of the older series). And you still haven't addressed why it is that SM literally had no foreshadowing in any way during the last stages of XY, something prior series have had, even DP to BW had it in the form of Team Rocket being requested by Giovanni for a "special assignment," and before XY to SM, that was the transition that had very few foreshadowing elements.
What makes you think it won't be canon? Yes, the movie has a lot of contradictions to the original anime, meaning it's most likely not canon to the original anime. However, the movie also managed to do a tie-in manga between SM and itself, which is definitely unprecedented especially when, unlike most other animes such as Dragon Ball Z (where only two movies, three including Dead Zone, are actually canon, and that's only because those two "movies" actually acted more like back door pilots for Dragon Ball Super), the Pokémon Movies were generally assumed to be canon to the anime, if not from the specific events being referenced in there or specific locales being referenced, heck, even specific items being shown that characters only got in the movies and not in the anime such as Dawn's Lunar Wing, then at the very least due to Ash recognizing certain Legendary Pokémon that he encountered solely in the movies. That suggest that, at the very least, it's canon to the SM anime (not much point in doing a tie-in manga, if the movie isn't intended to be canon to SM, ESPECIALLY given how, unlike the other movies, there were quite a bit of contradictory elements that suggest it isn't canon at all), and by extension, SM is not canon to XY (and bear in mind that, unlike prior series, even BW to a certain extent, which usually had Ash going the next region, and thus the next series, actually foreshadowed and actually hinting at the next series in some form, there was literally nothing pointing to Sun and Moon).
Besides, it's not just M20 that's leading some of us to believe it, there's also what Rica and that Sound Director said as well (and if the writers didn't approve of what they had to say, at the very least they'd be brought to the office and read the riot act, at worst, they'd be fired).