Sorry You will have to print and mail your returns even if the child amends theirs. Once a ssn has been entered into the IRS you can't efile it again. You didn't have to wait for the amended returns to be done.
How to mail a return from the Online version
https://ttlc.intuit.com/community/printing/help/how-do-i-print-and-mail-my-return-in-turbotax-online...
Be sure to attach copies of your W2s and any 1099s that have withholding on them. You have to mail federal and state in separate envelopes because they go to different places. Get a tracking number from the post office when you mail them for proof of filing.