I'm tad stuck with S32 Design Studio since there is no demo or example code in library or download for KEA8 devices especially S9KEAZN8AMTG. I do not wish to use codewarior.
Do you have working code with simple UART and flashing LED (with ADC12 interface?).
We do not have specific KEA8 example code developed in S32DS, but there are example drivers for KEA128 developed in S32DS that can re use with KEA8, link below.
Also there is a Kinetis EA cookbook that includes baremetal start up examples developed in S32DS, this could also be a good reference for you as well.
I hope it will help you.