Both the home app and script editor at home.google.com can have multiple actions for one starter and also have the ability to include a delay in the actions. For what you are trying to accomplish, you would have 3 actions in your routine 1. Start playing the play list, 2. Delay for 1.5 hours, and 3. Stop playback.
What particular commands you would use would depend on if your routine was created in the app or in the script editor.
