Hello Owen,
Yes, the SBC needs 12V power supply.
S32K148 EVB rev.A

It seems to be just a wrong label.
You can test it with GPIOs.
PCC->PCCn[PCC_PORTA_INDEX] |= PCC_PCCn_CGC_MASK; /* Enable clock for PORTA */
PORTA->PCR[27]|= PORT_PCR_MUX(1); /* Port A27: MUX = ALT1, GPIO */
PORTA->PCR[29]|= PORT_PCR_MUX(1); /* Port A29: MUX = ALT1, GPIO */
PTA->PDDR |= (1<<27) | (1<<29); // OUPUT
PTA->PDOR |= (1<<27); // PTA27 HIGH
PTA->PDOR &= ~(1<<29); // PTA29 LOW
I can measure HIGH on pin 7, EVB rev.A
Regards,
Daniel