About the only way you could do it if it were a once in a lifetime trip, would be to take the first ferry to Capri, then the first ferry from Capri to Sorrento, then negotiate a taxi to take you to Amalfi and Positano leaving time for a short visit to Pompeii before heading back to the port.
That would be doable based on the traffic, but one traffic accidnet along the way and you might well miss the ship. Also, Pompeii is HUGE! You would really have to focus to see it in a short amount of time.
Hope that helps.