Can I amend return and receive Child Tax credit with renewed ITIN

[Alindsey90]

We filed our taxes for 2020 earlier this year and at the time my husbands ITIN was expired but our taxes were still processed and we received most of our refund. They changed the amount and we received a letter stating we did not qualify for Child Tax Credit due to expired ITIN. We have since renewed his ITIN so it is now active. Should we amend our return so we can receive the CTC? Will that even work? I doubt the IRS will just automatically send it or is that a possibility? Thank you in advance.

[DoninGA]

If you applied for the ITIN renewal after the due date of the 2020 tax return, May 17, 2021, you are not eligible for the 2020 child tax credit.

IRS Publication 972 Child Tax Credit and Credit for Other Dependents - https://www.irs.gov/pub/irs-pdf/p972.pdf

You must have a TIN by the due date of your return.
If you, or your spouse if filing jointly, do not have an SSN or ITIN issued on or before the due date of your 2020 return (including extensions), you cannot claim the CTC, ODC, or ACTC on either your original or an amended 2020 return.
If you apply for an ITIN on or before the due date of your 2020 return (including extensions) and the IRS issues you an ITIN as a result of the application, the IRS will consider your ITIN as issued on or before the due date of your return.