My understanding is that you have two choices, one is to change paper size and/or page orientation, or reduce the number of columns in the CrossTab.
You could always reduce font size, etc., but often that is not enough. Apart from those suggestions, my understanding is a CrossTab moves from left to right spilling over to a new page. I guess the point is it really does not scale to page size.
Perhaps other will offer alternatives to what I have posted or correct any mistakes in my comments.
Regards,
John W.