It looks impossible to me, and what use would an 18 hole tournament on a 9 hole course be?
I for one can only create 9 hole tourneys if only the front 9 holes are filled. See the check boxes next to the course's title? "Holes: 9 18"
I suspect that you created an 18 hole course, leaving some but not all of the back nine empty. That's calling for trouble, of course.