I was about to go off the first tee as a single behind about 10 foursomes, and I was told there was no one on the tee sheet behind me. So I decided to play one ball from the blue tees and one ball from black tees (tips). I did that for 5 holes, then a single caught up with me and I played from just the blue tees for the rest of the front 9.
The single left after 9, so I went back to playing 2 balls on the two sets of tees on #10, a par 3. I hit from the blue tees, then I hit from the black tees and it went in the hole. I made a par 3 with my blue tee ball. A twosome then caught me, so I went back to playing one ball for the last 8 holes of the back nine. Naturally, I played the rest of the 9 from the black tees. I played the entire back 9 with the twosome and posted a 9 hole score for the back 9.
Did I make a hole-in-one? Was it legal (USGA rules) to post that back 9 score? If so, what would I take on hole #10 other than a 1?