Ninth Bridge Patrol's ability doesn't care where the creature went or whether it's a creature in its new zone. It may have died, been exiled, returned to your hand, and so on. It won't trigger if an object remains on the battlefield but ceases to be a creature. It won't trigger if a creature phases out.

If Ninth Bridge Patrol is dealt lethal damage at the same time as another creature you control, it won't receive a counter from its ability in time to save it.