Login to KUCCPS portal and go to
https://students.kuccps.net/account/. You should be able to see your KCSE results.
Your KCSE results data will be available in your account once revision of courses starts
If it is not available even after revision of courses has started, then call kuccps via 0205137400, or 0723954927 or 0734879662 for your details to be updated.