I've been wanting the ability to use the child directed setting with Admob and I think I've finally got a work around and wanted to share in case anyone else is looking for something like this.
This is a good setting to have if you're worried about what information about users Admob is collecting from you, especially with regards to COPPA regulation.
So here's how you can try out my solution (let me know if you notice any issues with it!). When you get to the point where you are adding the Admob plugin to Intel XDK, use this one instead:
Plugin ID: com.cranberrygame.phonegap.plugin.ad.admob
Don't check the box "Plugin is located in the Apache Cordova Plugins Registry"
Repo URL: https://github.com/russellrain/com.cran ... lddirected
This is just a fork of the cranberrygame repo that is referenced by the official admob plugin. I've just added a line (builder.tagForChildDirectedTreatment(true);) that sets the child directed setting.
I can't guarantee this will work for you or that I will actively keep my fork of the plugin updated in the future, but for now hopefully this might help some of you who are looking for this same thing—hopefully someday in the future we'll get official support for this feature.
edit: I think these instructions might not work perfectly with newer versions of Intel XDK, but hopefully it's enough to get you there. I'll have to update these instructions later.