The first Discovery novel was supposed to be "canon". Teaming up Spock and Michael Burnham. Then came Discovery season two. It is always best to err on the side of "not canon", because even if they say it is, odds are it'll end up contradicted in a major way somewhere down the road.
Canon vs. not canon doesn't really matter at this point though. The question really should be if it's intended (but non-essential) setup for Season 1. I tend to think it is, even if it will probably later be retconned.