Writing Tutor Recommendations for High School Junior

My son has identified a goal he needs some help with, and it occurred to me to reach out to the BPN community for writing tutor recommendations. He wants to be able to come up with an idea for and write a brief essay in 40 minutes so he can do that a few times on an AP test this spring. We're looking for a tutor who can help him overcome the challenges he's identified: One is a streak of perfectionism, which causes him to doubt what he has written is good enough. The second challenge, which leaves him staring at a page for long periods of time, he has named as writer's block or not knowing what to say or how to generate the sentences to write. Anyone had a good experience with a writing tutor for a teen they could share?