Can the OSI Alarm System be programmed to automatically arm and disarm every day/night?

Yes you can set the OSI Alarm System to auto arm/disarm based on your routine. The instructions is on page 12 of the user manual on how to do this.  

• To program timed Arm: go to Main Menu > Clock > Timed Disarm. Then select + and - to adjust time, Select "On" then Select "Confirm.

1. To program timed Disarm: Go to Main Menu > Clock > Timed Disarm. Then select + and - to adjust time, Select "On" then Select "Confirm. 

Also, you can set Alexa and Google Routines to automatically arm the alarm system every night or by voice command such as when you are wanting all the lights to to shut off and arm the system at once.