SMU has clinched the ACC title berth. The other ACC team will either be Miami or Clemson. Miami has the inside track since they control their own destiny.
Miami plays their final game at 8-3 Syracuse. If the Hurricanes win, they will play SMU in the title game; if not, Clemson will play SMU. Clemson's last game is non-conference against South Carolina.
SMU's only loss was an 18-15 loss to BYU. And while they have a couple of wins that were ranked 16 and 22 when they played them, they have not beaten anyone currently ranked in the top 25.
IMO, SMU and Clemson can only make the playoffs IF they win the conference championship game. I can't imagine SMU losing the conference championship and then making the CFP. I also don't think Clemson could lose the championship game and make the CFP. The only question is whether Miami could.
So for it even to be a discussable topic IMO, Miami would have to win at Syracuse next week and then the following week lose to SMU. But IMO a loss to a team that would not currently be in the CFP in their conference championship could knock them out anyway.