How can I insert a Youtube video into my Captivate 9 responsive presentation?

This video shows embedding a Vimeo video into a web object but the process is the same.

Add Vimeo Videos to Your Adobe Captivate eLearning

Try using the Web Object instead of the Youtube learning interaction widget.  Most users seem to find that they get better results with it.

Possibly... because certain sites block iframes from being used. I think YouTube is one of them. So you wouldn't be able to feature it in the web element thing (can't; remember the correct term for it). This is why certain websites work and others don't, Yammer is another site that won't load either.

The alternative would be to insert the video directly into the project or link out to it so a user clicks something and it takes them to YouTube.

Someone more technically savvy I'm sure will be able to confirm.