I'd go to $11M if it's an 8 year deal. I wouldn't love it, but you basically can't afford to lose him, unless people really want Brandon Carlo or Matt Grzelcyk as the #1 D on this team, because you're not finding a bargain on the free agent market. McAvoy's a top 5 defenseman in the league at 23 years old. You don't let that player walk away, and you're never going to get a trade package of equal value.
He's going to get at least $9.5M. Werenski just got $9.6M for 6 years. I don't know why McAvoy would take a cent less than that. Maybe Sweeney argues that Columbus had to bribe Werenski to stay, which is true, but McAvoy's agent won't care. The price is also just going to keep going up if they wait. My opinion is they should have had a deal ready to sign at 12:01 on July 28th, but I know there might be some cap considerations there.