Joint filing. Received 1099 for $9500 (contractor/part time) earned in MD. Need to pay about 15% to MD? If so, which form / where to submit?

I am a military spouse, FL resident, living in MD, earned $9500 in MD, and filing jointly with my husband. I looked nonresident booklet online but cannot be sure which form to use. 505? 505NR? 505DU, 505X, or 515? Or something else...?