Is money earned from working in sports betting permissible or impermissible, and is the money purified after the Imam's fatwa considered permissible, or are other matters required for repentance to be accepted?

If sports betting is forbidden, then your work in it and what you earned from it are unlawful. You must repent and dispose of the unlawful money by spending it on charitable causes. However, if betting is permissible, then your work in it is lawful and your earnings from it are permissible.