A mixture over the years..........
Afterschool ran a summer club which was cheap, but he didn't want to go to that after P5 (yr4) as it was mostly younger years and "boring".
dh and I taking annual leave at different times
dh working long days at weekends and taking mid week days off (self employed)
Reciprocal arrangements with other parents. ds was friends with a boy whose mum only worked 2 midweek days and was more than happy to have ds to keep her own son entertained. We had hers back on her working days.
Niece (17) was off college some of the same days and covered a couple of days
Local leisure centre did full day clubs where they had the full run of the centre and could swim, skate, etc. Even younger teens would go to it to hang out all day with friends.
WFH for a few days if stuck and work are supportive, but don't take piss - only an option if kids are more independent/older and you can flex your work. Didn't do this much as it is a boring option for dc too.
We were "lucky" with dh being self employed he was flexible, but it cost us a lot of money we could barely afford then if he wasn't working FT during those weeks and put a lot of pressure on him if he had to juggle jobs that took more than a few sequential days, or ran over, in customers homes.
I, more dh who was a bit of latch key kid from a young age, wasn't comfortable leaving ds at home alone at all, especially as we also had a medium/large dog at home - a big soft lump of a Labrador, but I could see ds inviting friends in, or leaving a door/gate open and I don't think children should be responsible for or left unsupervised around any dog.