Is there a Japanese word for Bonsai Master or Bonsai Creator?

Yes, the Japanese Word for a Bonsai Master or Bonsai Creator is "bonsai-shi." The term "shi" in Japanese indicates a person who is a master or expert in a particular field or profession. So, a bonsai-shi is someone who has achieved a high level of skill and expertise in the art of bonsai cultivation and design.