I've read your post where you said she's only 9 weeks which is a bit young to be away from mom, if she was wild shed still be with mom untill about 14-16 wks which is when the mom cat turns on them and drives them away to sink or swim.
If you look on the feliway site it shows you common stress factors for cats.
I've never had to litter train as all ours came from the breeder litter trained at 12 weeks but if you look it up on the Internet I'm sure you'll find plenty of advice on how to do it sounds like you need to go back to basics with her and start again.
Females wee everywhere when they first come into season too, and make a different calling miaow. I think a season at 9 weeks is unlikely but not impossible. Certainly my cat was trying to mate with his sister at 16 weeks but the mom was fed up with both of them and trying to drive them out (bit hard in a semi).
I'd start with researching litter training at first and teach her again.
And don't use normal cleaning products or disinfectant where she wees, some have ammonia in them which attracts them back to the same spot. I think your meant to use washing powder/liquid and then loads of bicarb when dry to neutralise any odours.
I was advised when I adopted my kitten from Cats Protection, not to use anything other that water to wash the litter tray itself. Have you used anything that smells strongly that might have put the kitten off? Being too scrupulous can have an adverse effect.
Fluffy is right about cleaning the accidents up, biological detergent solution or a special enzymatic spray like SimpleSolution from pet stores is best. You could try soaking up a wee with some litter and putting it in the tray after you've cleaned it, just to remind the kitten where it needs to go. I'm also a big fan of making a fuss/praising a pet when it does the right thing, during the retraining if you see her starting to crouch, pop her on the tray, and when she does it there make lots of fuss, stroking, tickling etc, you could offer a kitten treat as a reinforcer of the desired good behaviour.