This problem seems to be with the Operating System and you may need to reinstall it in the device.
You may need to take it to the service centre or you can do it at home with a computer.
Check Full Device Specifications Honor 9N
Honor 9N has got an Octa-core (2.36 GHz, Quad core, Cortex A53 + 1.7 GHz, Quad core, Cortex A53) processor bundled with 3GB of RAM for optimum performance. You can smoothly play high-end games on this device.
ou can see detailed specs here: Honor 9N