Home alone

Our son turned 11 about 4 weeks ago and is now in his last year of primary school. When he moves up to High School next September he will have to catch a bus to school as the High School is in the next village about 3 miles away. He will have to leave the house about 7.40 am and then come home sometime after 4 pm.
Since October half term last year, he has been walking to school on his own if I am on a late start at work. Since half term of the summer term this year, he has been allowed to walk home on his own when my husband was on his day off. New key cut for him and attached to his rucksack so that he can't leave it in the door when he got home!
This term, we have made a decision to try and get him more confident with coming home alone and have allowed him to walk home to our house each day and be home alone for approximately 45 minutes if I am on an early start if he has no after school clubs, in which case he would not arrive home until after I have got home.
Tuesdays are football after school club. I got home at 4.15, he should arrive home by 4.30 at the latest.
4.50 pm - no son. It is parents evenings this week along with a book fair at school. He volunteered to help yesterday, which was no problem, so I thought maybe he had popped in there again tonight after football. Walked down to school - no sign of him, book fair packed up, no football coach around, saw the after school club supervisor - who knows him - but she hadn't seen him either.
Looked in and around the school - still no sign.
Came home and started to phone people - started with one of the football coaches - his mum runs the local Guide unit so had his phone number! This coach hadn't been at football this evening so couldn't tell me - but did offer to ring around if I hadn't found him later on.
Rang 3 other mums who all said the same - he had been at football, but they hadn't seen who he left with! Panic starting to set in.
Rang a few other friends houses with no luck.
At 5.20 pm decided to bite the bullet and ring my husband just to check if he had told him to go somewhere else after football.
Husband hadn't - definitely not a happy bunny. He was working late tonight about 50 minutes drive away and would not be home until later. Told him I would ring him and let him know when I found him.
Decided to go and drive around our village - as I pull out of the drive, one grass covered child cool as a cucumber walks into our cul-de-sac!
Parked the car and asked him where he had been. Ben's house he replied! Where does Ben live I ask -on the green round the corner from school!
Once inside the house, I explained to him - calmly for me - about how worried I had been and that I had been ringing lots of parents trying to find him!I also told him how sick I had felt not knowing where he was. He should have come home straight from football, or at least rang me from Ben's house to let me know where he was and what time he would be home.
I also said that if he couldn't be trusted to come straight home, then he will have to start going back to the childminders after school - this is not something he wants to do.
Rang my husband but he was unable to come to the phone - his boss took the message and said he would let him know. 5 minutes later, hubby rings back. I explained to him where he had been and that we had discussed that it had been wrong to do it. Hubby's reply - keep him up until I get home !!!
That is not a good thing. Told son that daddy is not happy with him and that the mood he will be in tonight when he gets home, will be a mood he will never want to see again, so tonight will be very fraught I think.
Of course I am now wondering if this is a good thing allowing him home after school on his own to build up his confidence and for him to get used to being home alone?
I am hoping that after this episode this evening that it is something that will never happen again but do I trust him not to do it, or do we revert back to him going to the childminders?
Will have to wait and see the outcome of the discussion between him and dad tonight!