What you are planning is very different. Your best bet maybe to write child care will be provided during the ceremony; on those people you do not want their child at the ceremony. You may get a few phone calls, with people not understanding. I have know 5 year old that behave better than 10 year olds. There are a lot of children between 5 and 8 that will behave during the ceremony. Children over 8 that would not.
What a bizarre age cutoff. You need to rethink your plan, because the one you have is rude and impractical, quite simply. Either invite children to your wedding and reception or don't. You can't invite them to half. Most parents know that if their children are being disruptive they should take them out of the ceremony. Parents aren't likely to use child care from strangers. You address the invitations to those invited, period. If that includes children under eight, invite them by name. If it doesn't, only write their parents names. The parents will either find their own child care or decline the invitation. You will only cause yourself problems by inviting half the family. In other words, what will you do if there are siblings 9 and 6? Send the younger one away? You're only going alienate your guests. If you're that worried about them disrupting your ceremony, just invite adults.
