Ok ... YES you are NOT required to claim any dependents HOWEVER if you amend later to add the child back the child credits will NOT be allowed. If you can you should WAIT to file a return until you get the SS#.
If you are worried about the stimulus check the IRS will also take your 2018 return into consideration AND you will get to reconcile the shortfall on the 2020 return. So waiting will not hurt but filing without the child definitely will.
