In order to activate parallel processing, please use the reports instead of transactions. In the reports you'll find the parameter "parallel processing" in the UI.
Please find the corresponding reports to each of the requested transactions:
KKS1 => report RKKKS1N0
CO88 => report RKO7CO88
KKAO => report SAPKKA07BG or SAPKKA07 (depending if you're looking to run at plant or order level)