Should I retake the SAT?

I got my October SAT scores and I’m satisfied with my total score: 1520 composite (Math-770, Verbal-750). However, I got a 14/24 (5/4/5) on the essay. I’ve taken the old SAT as well (2190 composite with 800 Math, 710 Critical Reading, 680 Writing with 8 on the essay). I’m an international student who will be applying to top schools (in particular, Stanford) that require the writing portion. I’m wondering how much does the essay matter for colleges that do require it and is it advisable to take the SAT again in December only for the essay?

no. dont bother.
your essays will give colleges a better idea of your english writing skills than taking the SAT again.