Hello Hari Prasanth SM,
You may change the cores frequencies or disable cores from Linux. You may find more details on the i.MX Linux Reference Manual on the CPU Frequency Scaling (CPUFREQ) section. This document is available as part of the BSP Release documentation.
As for power measurements, you may use Application Note 12778 as reference (link below). This application note has a couple of scenarios, but it holds all publicly available power consumption measurements and may serve to get an estimate on what power consumption you can expect on your application.
https://www.nxp.com/docs/en/application-note/AN12778.pdf
My apologies for the inconvenience!
Regards,