This is not a behavioural problem, it is dirrohea that is causing this.
Please feed your kitten a bland diet of chicken rice, boiled fish for 2-3 days, (this is too empty his gastrointestinal system) then introduce a high quality food such as dry IAMS, HILLS, PURINA, JAMES WELBELOVED etc.. of a kitten brand also.
WHen you introduce this food it must be done over about a week
DAY 1 - introduce 4-5 buiscuits of the new food with his chicken
DAY2 - Introduce a 1/4 buiscuits of the new food and cut the chicken down by a 1/4
DAY 3 - Introduce 1/2 , cut chicken down by half
DAY 4 - 3/4 buiscuits - 1/4 chicken
DAY5 - 100% new high quality dry buiscuits - AT this piont there should be no dirrohea.
If there is still dirrohea and your kitten is still defecating all over the house add more cat litters, try changing the cat litter , please make sure that the cat litter trays are clean (some cats will only go in a clean tray, or a dirty one for that fact!) Worm him for gastrointestinal worms round worms and tapeworms as these can cause this problem
If you need any more information please ask me another question by adding to this one
Hope this helps