Ds1 loved staying at home in year 6, for 1 or 2 days over 1/2 term. So he was only 11 then. That was the first time I tried it. But I only work 3 short days 9-3, and I work 5 minutes away, so this worked perfectly. For us, admittedly. By the time he was 12, he has already spent one term at secondary and had grown up alot. He had no interest in childcare! He didn't want to go to the childcare with Ds2, 6-11 year olds.
He was at home with me one day, at home alone the next, off out playing football all day at he local sports centre all day the next, in town at the cinema the next, at home playing x box all day the next!! So it continued. I didn't need child care for him.
Some children will need it. Others won't. Depends on their maturity, their personality. And your working needs. Admittedly if you are out the door for 12 hours, with a long commute, 5 days, that's a different need to mine.
But are many other posters here posting thinking about this for the future? If so, you may be being unreasonable. I think you'll find that most 12-year-olds have zero interest in going to any childcare club. See how it is when you get there? / nearer the time? You might be surprised.