One of the new features in 9.4 is the ability to sort and reorder sub categories visually from the admin.
In the Admin click on "Menu," "Catalog" and then "Categories."
Now click on "Child Categories."
Now click on the Enable Sorting icon (one arrow up, one arrow down).
Click on "Enable Sorting." When you click on this a window will come up making sure you don't have any changes that you haven't saved. If you don't, go ahead and click "Ok."
Now click on the Enable Sorting icon again and then scroll all the way down to the bottom to "Edit Display Order."
You can now reorder your sub categories by simply placing the numbers according to how you want the categories to display, 1 being first.
If you want to use the move tools, click on a category and then click back on the "Display Order Menu" icon. You will now see that you can either:
If you have a lot of sub categories and want to move one category to a particular position, you can click on the sub category (Sub Cat Three) and then click on the "Display Order Menu" and then click on "Move to Position."
You will see an icon that appears and looks like a pin marker next to all your other sub categories. Now click on the sub category where you want to move to and then the sub category will move to that position.