[stony ground]

I'm sure there are wiser voices than me here, so I would defer to them. However, having seen a church deal with similar issues in the past, I think it's important to give the individual every opportunity to be in church where God has planted them. Worshipping in church services should not come with many strings attached, and involvement in other ministries could be commensurate with their level of commitment to upholding the standards of the church.

I do agree that it would be unwise to allow this person to renew their involvement in the youth ministry, but (as someone who has had a family member in a vaguely similar situation) I would advise you to frame your decision to exclude this person from youth activities as being as much for their protection as anything else. They apparently committed a crime with their first indiscretion, and to involve them in youth activities would open them up to unecessary risk of being accused of another offense (even falsely).

It is a tricky situation, no doubt. This person is going to have to understand that being welcome to worship and being allowed to be involved in a leadership role are two different things.