I tried putting my cursor in the window containing the icons and scrolling and it worked! However, from a user point of view that is not the proper mechanism to use. Up at the top of the screen where all of the resources are displayed you have scroll arrows to move left or right. I suggest that you do the same thing with the Executive Orders window. Using the mouse wheel, which is usually used to scroll up and down, to scroll left and right is not intuitive.
Putting cursor in the window containing the icons and scrolling doesn't work for me. However as I said, only 7 Executive Orders are showing with 2 not available for selection. I have no idea what the missing ones are or why they don't appear. I'm playing as Terrans - are some not available to that Civ?
Update - OK, I waited for my control points to increase (up to 40) and now I'm showing 9 with all 9 available, but I still can't see all potential Executive Orders by scrolling.