The service is called "bind9-resolvconf" but you said you ran "sudo systemctl start bind9-resolv.conf" and "sudo systemctl stop bind9-resolv.conf". Look carefully at the spelling.
The service is called "bind9-resolvconf" but you said you ran "sudo systemctl start bind9-resolv.conf" and "sudo systemctl stop bind9-resolv.conf". Look carefully at the spelling.