Are you sure about the unit model is it an Antminer s9? Or a clone one?

The kernel logs are a bit different compared to my Antminer s9 I don't know for the C5 controller but would you mind to try to flash it through the SD card?

You can follow the guide from this link below

- https://support.bitmain.com/hc/en-us/articles/360019493654-S9-series-S9-S9i-S9j-S9-Hydro-Control-Board-Program-Recovery