Tried to Inline CSS with AdvAgg but still get errors in Google My Right-to-left site uses clean Bootstrap subtheme and has CDN, Internal caching (including Boost), Minification, Compression and aggregation, but still I get very low grades with all that has to do with CSS performance. Therefore I tried to inline all the CSS in my site via AdvAgg (please see image), what helped me in another theme, but not this time... 

Is there anything else you think I should try?
Your setting for Inline CSS on specific pages is wrong. The path you should set is:

node/*