The "es" is optional in your example, you can leave it out. And no, you don't need Konjunktiv, you just take indicative mood for that.
It used to be possible to alternatively use Konjunktiv 1 for "isst", namely "esse", analog to:
ich will, dass sie gehe
but that would be stilted and dated.
dated example 1
dated example 2 (with explanation)