Whatever SD ammo feeds thru you 709 that you can afford to shoot a little on the range will do. I use WWB Personal Protection Series 147gr JHP - it's inexpensive and feeds fires thru all my 9MM's. When I go to the range I generally shoot a mag or two thru my CCW just to be sure all is still well, then get down to the fun part - shooting half dozen different guns. for a few hours. LOL
Welcome to the forum.