They are the same meaning. It depends on the situation but I use 一回　for daily conversations and 一度 for write a sentence or a formal way to say. Good Luck!

No difference. Both 回 and 度 are used for "how many times". It's common to say 1度 and 2度, but it's a bit less common 3度 and we never say 4( or more)度. Be careful.