Sorry to say, but Creative Writing is the ultimate 'soft' subject. A lot of universities will not accept it as an A level, or will only accept it as a fourth A level (much like General studies). If you're thinking of taking it to form part of a university offer, then you can pretty much rule out a competitive application to any decent uni.
Creative Writing is more of a leisure activity than an academic pursuit (English Lit would be the choice there). So by all means do it if you want to and find it enjoyable, but be aware of its status.