It means Creative Use..that means if you area designer you can use it in a kit, to sell, by like recoloring it or whatever. P/U is personal use which means you can only use it for your personal projects not in a kit to sell.
You could also see it as commercial use, it means the same thing, for designers' use and they can sell. I prefer calling it commercial over creative because if you ask me EVERY kit is for creative use right? we're creating something with it? Just my thoughts.