If we determine that God is good, then we are exercising our moral judgement. But we get our moral judgement from God, because he created us. So we haven't got an independent method of judging God. So only God can judge himself. In order to judge himself, he must compare himself to some standard. Did he determine the standard ? Well, yes, because there is no other authority. Did he have good reasons for that standard? Well, you might think so, but what makes them good reasons? The reasons can't be good, because that requires a standard by which they can be judged. I suppose he could make up reasons, but that wouldn't make them good. Therefore he didn't have good reasons. Therefore the standard is arbitrary. Therefore, for God, goodness is arbitrary. Therefore God cannot be judged to be good. So the only logical answer is no.