Never send the item to an address not designated at the time of payment. If the buyer wants it sent to a different address, the transaction would have to be cancelled and repurchased with the corrected address. This is to protect you from Item Not Received claims, one of the few seller protections offered by eBay.
There is also a scam going around where a poser pretends to be your buyer and requests the item be addressed to a different address than that given in the transaction. Always match up IDs to ensure you are communicating with the actual buyer. If you fell for that one you would lose the money and the item with no recourse. You would be forced to refund the actual buyer and your item would be on its way to a thief.
As for the situation with your current buyer, as long as the item shows delivered via tracking to the address given at time of check-out, you are not liable for the refund. Upload the tracking number into the case notes which is required. eBay will close the case in your favor and remove the feedback. It is the buyer’s responsibility to give the proper address at checkout, and to provide a safe area for the package to be delivered to.
