Non Profit for Youth Sports Team
Depending on your donors you might need to form a Non-Profit Organization and file for all necessary exemptions with the IRS and the state. If they expect those donations to be tax deductible then that should be the way to go.
I'm not sure about sponsors, since it is possible that sponsorships can be recorded as advertising expenses (for the sponsors) and advertising revenue (for the team), however those questions are better addressed with a licensed CPA.
Your Non-Profit will need an EIN (Federal Tax ID), what you referred to as TIN. In general I would recommend you to consult with a CPA to see if Non-Profit is the right direction in your particular case (keep in mind its pretty costly and takes a few months to set it up correctly, including obtaining all the exemptions).