Web objects and youtube videos are not supported when your published output is in pdf format.
However, if you are publishing in SWF/HTML5 format, they will work, provided you are playing the content from a server and not locally. Also if you publish your SWF/HTML5 output on an LMS, it will work fine.
For all the necessary details pertaining to embedding of youtube videos and web objects in your presentation, please refer this help document- Presenter Help | Embedding videos and web objects
Let me know if you need any further details. Please mark this answer as correct if you find it helpful.
Adobe Presenter Engineering Team