I have the same problem with my male kitten , he is almost 10 months old. I have another female cat using the same litter and we don’t have any problem with her. My male kitten has as well loose poop since the day we adopted him. He eats very well and very active and playful but she has this constant problem with the poop ( he made the test of worms many time and it s negative) and the urine that doesn’t clump!