You can add as many keywords as you want and the SEO Live Assistant allows you to place in keywords that you store in Briefcase.
The main keyword will be marked with a STAR symbol (you can always change your main keyword). The SEO Live Assistant will calculate and show Optimization scores for all keywords you’ve optimized your text for.
So, maybe you have 1 main keyword, 3 secondary keywords, and 5 other keywords which you want to place inside the blog post, to help Google understand what the content is about (eg. adding “magical wands” “Diagon Alley”, etc. to a post about “Hermione Granger”)
That would be a total of 9. You can manage that as you like and we don’t limit you.