I think it depends on the child , the area you live in - how close to school etc .
I live far from my sons school as we never moved him when we move so he would have to get buses home , so no way for me ( my sons also 10, in y5 ) but I’m very lucky in the fact i have his nan who does drop offs and pickups for me and keeps him until I finish. I get home about 5 and he would get back here about 345/4 if Nan dropped him straight back and we have toyed with the idea of him being dropped home ( I do have a 17 year old who would be here from 430/445 ) but decided to leave it until he’s in y6 . Then see how we feel .
A lot of children in my son’s class walk home alone . I don’t know how I would feel about that as my son has never been out anywhere alone , not even the local shop .
I would say closer to 11 would be better but some children are more capable than others .
Realisticly - I think for most at that age , safety in the house isn’t an issue . I know my son would just be sat in his room on his game , just like he would be if I was there . He wouldn’t answer the door or anything . But , it’s things you don’t think of . I left 2 of my children in the house while we went to Tesco a 5 min drive away ( my 15 yr old and 10 yr old ) we’ve done it before and they have been fine , but we had a power cut and the alarm started going off and they both freaked out ! Called us crying and my husband had to drive back , leave me shopping , to sort it . Very unlikely thing to happen but something that could happen , just one of those things you don’t think of .
Also when i first started letting my older one come in alone from school ( she’s autistic but capable of that I was only getting home 20 min after her and had her dad around the corner , contactable by phone , neighbours who I knew well ) but one day her key just wouldn’t work in the door and she panicked and was calling me repeatedly, upset . So I did have to then change it to her getting dropped home to her dads and collecting her .
Is there anyone who could walk her home and help her get in ? Is there a neighbour who would be willing to just be there if something happened - that he could knock on to if worried about something ? Are you local to home and contactable - so that you could be on the phone to him if needed ? Could you get a ring camera so you can see and speak to him if there was a problem ? Could you get cameras in the home ?
It just all depends . I don’t think you are unreasonable for thinking about it - for some it would be totally unsafe , for others not .
For me , as it’s not a massive amount of time at home , it would be the concern of getting home from school rather than the concern of him being in the house alone for an hour or so x