See the checkboxes for the character names, under Usable by? Check their names and they'll be able to use them.
that said, here's some extra info that might be useful. you don't need to use the 9999 HP and MP. The fields in front of those are for percentages, so you could just set them to 100 and leave the second fields (the ones you currently have filled with 9s) to be 0. It's especially useful for items that recover half of a person's max HP, etc.