1. “他人很好”means “he the person is firendly” . 2.the correct form is "℃"，you can pronounce it as "摄氏度 shè shì dù", but Chinese often just say "度 dù" 最低气温9℃ === 最低温度9度（摄氏度）

There are two meanings of "他人". Here is the first meaning. 1, the person. 他这个人 short for 他人. in here: 他人很好=the person ' s a nice guy. 2, another person. 其他人 short for 他人. like:如果你不能确定他人的感受，你可以提问。 If you’re not sure of how another person feels, ask them。