If a marker is clicked near the top of the map viewport, the infowindow loads outside the viewable area and the map must be dragged to see infowindow content.
Ideally I don't want the map to auto pan. Is there a way to load the infowindow in a different direction, e.g. if the marker is at the top of the viewport to display the infowindow in a downward direction.
No, you can't open google's default infowindows in a different direction since you don't implement your own infowindow class. But you can disable auto-pannnig simply passing TRUE to disableAutoPan property of InfoWindowOptions object like documentation said.