At U8 I would separate match minutes from using attendance as a punishment.
If a child turns up on Sunday and is part of the team, I still want them to play meaningful minutes. I would not cut them to ten minutes because they missed Tuesday.
But repeated non-attendance is a club conversation. Training matters for learning, friendships and being part of the group, and families should understand the commitment they signed up for.
I’d speak to the parent first and find out why. Sometimes it is logistics, family circumstances or another activity rather than lack of interest.
If the club has an attendance expectation, make it clear and apply it consistently.
What I would avoid is making an eight-year-old pay on matchday for an adult scheduling problem.
Deal with the commitment issue with the parent; keep the child’s football experience development-focused when they are there.