You receive an IFR enroute clearance stating: Clearance expires at 0920. What does it mean?

Question

Question ATPL - Airline Transport Pilot license - Air Law

QuizVDS · Accepted Answer

If not airborne until 0920, a new clearance has to be issued

QuizVDS · Answer

The take off clearance is expected at 0920

QuizVDS · Answer

Do not take off before 0920

QuizVDS · Answer

After 0920 return to the ramp and file a new flight plan

Id 108 - ATPL - You receive an IFR enroute clearance stating: Clearance expires at 0920. What does it mean?