Why can’t Redmi 9A use Feng Shui Compass?

Because of the lack of magnetic sensors.

Only if the magnetic sensor is configured, you can use the Feng Shui compass and use it to determine the direction.

You can contact the merchant and ask the reason. Either ask the merchant to add it or recycle and reissue a 9A with a compass. Go to the official Redmi flagship store and ask the staff to find out the specific reason. That is to change the phone and replace it with the original one. There is a compass configuration on the configuration