So either you believe Booker intentionally goes against his coaches plan at times
Or..
He is doing what is expected of him to the best of his ability
Personally I think the criticism of Devin Booker gets misconstrued. During game threads it can be any number of players that come under the magnifying glass much like watching a Cardinals game. A lot of players get criticized there as well like Kyker Murray, A.J. Green or someone else depending on the game.
With the Suns, some nights it's Deandre Ayton, Mikal Bridges, Landry Shamet or someone like Elfrid Payton that draws the frustration of fans. I mostly take it as part of the ebb and flow of emotion that goes with the game.
In regard to Devin Booker I don't criticize him a lot because there is not a lot to criticize. However, there are moments in a game where it seems like he has to play the role of Kobe Bryant for a moment or two and feels compelled to force a play. This used to happen frequently when the Suns wanted a 2/1 near the end of quarters but not so much anymore. It's almost like he says I'm going to do this, everyone clear out even if the options close down. Also there are periods where he falls in love with the 3-point shot when it's not falling.
I think a lot of fans want Devin to eventually mature as a player and understand there are times in the game where he doesn't have to take the shot or he improves his shot selection much like Chris Paul. The thing is though, Chris Paul is 36 years old. It's going to take time for Booker to get there.