Why can't a 9yo play a game with 7yo rating???

If you have only 1 kid I understand it may be possible to monitor their PS4 activity, however with 3 youngster at 2, 7 and 9 years old it's a lot harder.
Especially as both parents are working busy full time jobs with the father's job requiring him to work while he is at home as well.

You are not supposed to have to constantly monitor your children while they use their gaming console, that is what the parental control function is for.

The kids are well behaved and they are not allowed unlimited playtime on the PS4, but the time they are given should not have to be monitored.
While the kids are playing on it the parents get time to focus on stuff like putting the smallest one to bed, cleaning up after dinner, doing chores that need to be done around the house, answer som work emails etc. etc.

The matter is still that the game has an age rating of 7, but you have to be 15 or 16 years old to play it without removing important safety functions preventing your child from accessing harmful content.