Wifi Internet filtering in church sanctuary

[Tech in SC]

I have a church that wants to fire some wifi into their sanctuary and filter it as to not allow objectionable content.

Getting the wifi into the sanctuary in itself will be a challenge (considering the budget I'm working with as well as the building is wall after wall of cinder blocks... no drywall in this one.)

I think I have a long range wifi solution using Ayrmesh but I'm open to suggestions.

My main question is what would you recommend for content filtering? It can't be client side filtering since anyone in the church sanctuary can access the Internet with whatever devices they may have.

All comments, recommendations, thoughts are appreciated.