1. You do not have to file a separate return for Sep to Dec 2021 as you had no US source of income and you were a nonresident. You must file 1040 NR if you are a dual-status taxpayer who gives up residence in the United States during the year and who is not a U.S. resident on the last day of the tax year.
Write "Dual-Status Return" across the top of the return. Attach a statement to your return to show the income for the part of the year you are a resident. You can use Form 1040, U.S. Individual Income Tax Return as the statement, but be sure to write "Dual-Status Statement" across the top.
2 Yes you can not claim the standard deduction if you are filing the dual-status return. TurboTax does not support 1040NR. You will have to use Sprintax.
Dual status
