Hello! There are ferry ticket outlets in the malls (just ask the concierge or mall guard where they are located). There are also ticket outlets in the Pier (but it's far from the city center). You may also buy from travel agents but my guess is that it will be more expensive. I see you;re walking at the perimeter of Xavier University, ahead is a street called Mortola and in it is a big mall that sells tickets. You may also try online booking (havn't tried that one yet :) ). Enjoy Cagayan de Oro City!!