Minnesota 529 question. I opened a 529 for my son in Jan 2021. Can i use that 529 contribution for my 2020 state taxes? i wont have a 1099-Q for 2020.

Yes. You do not need any IRS or state form.  You claim the the contribution from your own records.  A 1099-Q is only for distributions, not contributions.

There is no federal deduction for making a contribution to a 529 plan. Some states allow a deduction on the state return. If your state is one, it will come up in the state interview; usually in the "Here's how (your state) handles income differently" section.

Minnesota taxpayers may claim either a tax deduction or a tax credit depending on their income, for contributions to ANY state's 529 plan*. A $1,500 tax deduction ($3,000 for a married couple filing jointly) can be claimed against Minnesota income tax. Alternatively, a tax credit equal to 50% of the contributions to accounts, reduced by any withdrawals, may be claimed with a maximum credit amount of up to $500, subject to a phase-out schedule starting at a federal adjusted gross income of $75,000.

*For a list,  of state plans, see:

http://www.savingforcollege.com/compare_529_plans/index.php?page=compare_plan_questions&plan_question_ids[]=437&order_by=plan_question_437

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