I mean, if you say so, I'm not convinced of that yet for a couple of reasons.
First off, Boeser is having a break out year this year. That is reflecting in not only his stats, but his all around play on the ice, he is a MUCH better player than we've seen the past two years. Plus, his shot is looking vastly improved as well, he's currently tied for 3rd in total goals scored in the league.
Secondly, Boeser has a proven NHL track record over the past 4 seasons. I would feel far more comfortable investing in Boeser with that track record, over Kaprizov's single good season. Especially considering that single season will only be a 56 game stint, it is extremely common for rookies (especially those from Europe or college) to taper off down the stretch as they are not used to the rigors of an 82 game schedule.
And lastly, Boeser has better NHL size. Now, we have seen a lot of smaller players be extremely successful in todays NHL especially in scoring roles, so this point needs to be taken with a grain of salt. But still, I usually tend to bet on the player with an above average NHL frame versus an undersized player when other factors are relatively equal.
But hey, that's not to say that Kaprizov isn't going to be a much better player than Boeser, but the argument of not paying him 9mil long-term isn't about that. It's about the risk in paying him that based on a minimal sample size, because if he regresses from his rookie season, it will cripple the Wild for years to come. They need to sign him to some sort of bridge contract from my viewpoint to ensure they are comfortable with what they have in him, even if it's just a 1 year deal.