If all 9 appear to act up in unison, then first I would suspect a intermittent connection on the common feed to the relays.
Have you identified the function of each output?
This may give you a clue as to what alarm is flashing, although I would have suspected an input to cause an alarm, the controller usually does not know the status of the outputs after it has left the connection unit.
This is why I suggest identifying the output functions.
Usually the only other way all 9 would drop out together is if they all have a common logic bit in the ladder that changes somehow?