The goalkeeper gets blamed whenever we concede

I would address this with the whole group rather than protect the goalkeeper separately. At eight, children often only see the last action. The shot goes in, so they think the goalkeeper caused the goal. I would help them understand that goals come from lots of moments and that nobody gets blamed. Keep it simple: we solve problems together and we react together. If somebody says “you should have saved that”, I would calmly challenge the habit in the moment rather than shame the child who said it. I would also make sure the goalkeeper is not receiving a big sympathy reaction after every goal. That can reinforce the idea that conceding is their personal failure. The aim is a team culture where players can notice mistakes without assigning blame.