I would say, 95 % percent the ships are on time in the ports. I think, they have enough scope during the night to make up a delay.
Only two times, we left the port later than scheduled, but arrived on time the next morning.
We often book independant shore excursions and we arrange that they pick us off the pier about 90 minutes after scheduled arrival on the port.
But if you have to tender, itīs much more difficult to make an arrangment for a pick off at the pier.