POTENTIAL SCAM/BREAK-IN ALERT

It all started when my son accidentally broke our garage door. I called my home warranty company and they called someone to come over. Pretty normal right? It all seemed to be normal. They scheduled to be there between 1-4pm yesterday. So I was delighted when my son called me to let me know they were there early at 9am. Keep in mind, no one shows up that early without calling to make sure someone is there. This guy did. My son handed him the phone and I talked to him. He said I didn't even need to be there and he would take care of everything and send us a bill. In itself, that's weird because most places require someone 18 or older at the residence. My son is 15 years old and on summer break. His mom was gonna pick him up later so it wasn't a big deal to leave him at home alone but now I'm kind of freaked out and here's why.

The guy fixed it. 100% great job...but he didn't leave a bill, a card, no contact info of any sort. Later at around noon, I get a call from the tech at the company we hired, informing me that he was running a bit early and he was on his way as long as I was home

....his company or any other company I could find in this area hadn't sent the guy who showed up at 9 in the morning. Free work right? Sure, but no one does free work. I called the police to report it just because it seemed really odd. It was my neighbor who finally made a potential guess as to why this happened but it's still a stretch. What if the guy was a former handyman or overhead door employee and he does this just to program an extra garage door opener and come back later to rob the place?

If you or ANYONE you know has a similar story or a potential answer please let me know. I'm trying to make sense of all this and potentially stop future robberies...if that's what's going on here at all