NO, you cannot apply for KMTC admission without a national ID. It is part of the requirements in the application process.
If you happen to be placed to KMTC and you are below 18 years, then you will be asked to report for admission when you turn 18. Your space will still be secured until you turn 18. However, these days you have to provide your ID number during application which means such cases of under 18 being placed should not occur.