first off, if anyone wants to pretend climate change doesn't exist, in my day, in that state, we would sometimes have high 60s lows (or at least low 70s most of the time) as early as late august. i vividly remember a hint of chill on some morning runs when i was first joining XC. in august. in texas. the morning temps have increased 5-10 degrees. it was around 80 this summer when it used to be closer to 70 in a moderate summer, mid 70s in a hot one. if it hit 80 in the morning it was like once or twice a decade. even on the high temp end, it might hit 100 occasionally. maybe dance around it a week. then go back down. none of this months at a time malarkey. most of the time 100 highs would be accompanied by 70 lows as it reflected a high pressure system and drier air. it is now 100 and humid. this is not normal here. people who come here and say "but texas is hot" are idiots.
during college i would come back and play summer ball here while i worked and games were 6pm weekends. you would roast. i didn't complain because i was working night shift one year.
second, i ran a couple meets in midday 100F heat which was gross and pointless.
third, on the guts of your question, texas is just now, this week, holding UIL football championships after the playoffs worked their way through. meanwhile XC was the first week of november. volleyball and other fall sports go deeper into fall than XC does. push XC state championships to now, run the season meets starting in september as temps drop. district mid-november. area weekend before turkey day. regionals first weekend december. state this week. fewer brains melted running scorcher meets with slow times. i never understood how 100F in the sun on a flat course prepared you to run what was inevitably a 60F overcast district meet over hills. which, i was good over hills in cool, and slow in the heat in a flat distance footrace.
fourth, i think there was one meet we ran with the JHS kids. other way of dealing with it is they -- as i always thought -- run their own schedules. they can run at 9 their place, we run at 9 at ours.