Turn off mac at a specific time to force bedtimes
macOS provides scheduled shutdown through Energy Saver.


  Use the Schedule feature of Energy Saver preferences to set a time for your Mac to automatically start up, wake, sleep, restart, or shut down.


Unfortunately this only allows for one shut down time rather than multiple.


  
  From the Apple () menu, choose System Preferences, then click Energy Saver. 
  Click the Schedule button, then use the checkboxes and pop-up menus to choose when to start up, wake, sleep, restart, or shut down.
  


https://support.apple.com/HT201988