“MY QUESTION IS: Do I have to file with the above scenario.”----->It depends on the amount of your MAGI, modified adjusted gross income, provisional income, I mean; since the amount of your MAGI is $9,348;$1,458*12/2+$600=$9,348. So, the amount of your MAGI(provisional income) is LESS than $25,000 for single filer, you do not need to file your US return with the IRS(no WA return since there is no income tax in WA). However, if you had net earnings, I mean the amount on Sch C line 29/31, from self-employment of at least $400, then you must file your US return. Please visit the SSA Website here:
Benefits Planner: Income Taxes And Your Social Security Benefits Are Your Social Security Benefits Taxable?