Ah, you need me to walk you through this? Okay, I'll break out my crayons.
We are smack dab in the part of the year where acts start announcing their fall tour dates. For example, Billie Eillish and Post Malone have released portions of their tour dates within the last 24 hours. If you go to Google and type in "Announces Fall Tour" you're going to see hundreds of articles published in the last 24 hours about dozens of acts announcing their tours. This is going to keep happening in the coming weeks.
Now, here is where things get really tricky so I'll ask you read this very slowly: they don't decide when and where to have a concert a few days before they make an announcement. Generally, arena dates are negotiated and booked 6-12 months in advance. What you see on the calendar right now isn't going to be accurate in just a month's time. There will be more booked dates for October and November.
If that wasn't confusing, listen to this: you can't always "stage" an event the day of. Sometimes set pieces and equipment must be in place 24 hours before the event - stuff like pyro has to be inspected, tested, approved. So, there are days where the arena can't be used even though the calendar shows no events because it's either prepared or being prepared for the following evening's event.
Also, your original post about the number of dates was wrong. There are 11 non-NBA events at Toyota Center in October at the moment, not 9.
Now, stop being pedantic. Or just think.