@hotpot: Sorry to hear that you're experiencing this issue. Did you have you screen replaced by an authorised Samsung engineer? For clarity, did you mean that you're able to establish a charge on your S9 using your S7 charger, as you shouldn't have access to the battery due to the S9 being a closed unit? If you power off the S9 and connect it to your original charger, does this help at all? Similarly if you have access to a home computer can you try connecting the phone via USB to see if you can establish a charge in this manner?