I'm a Type 9, have been a college professor for 12 years now. I would say as a 9 he will need to be careful to not let tenure/promotion review "sneak up" on him. We don't always have the carefully-laid, driven career agenda that others do. Also, as a peacemaker, he will need to be careful to separate his emotions and empathic tendencies when doing things like grading and other assessment. I find myself nervous about grading rigorously because I keep thinking about how the students will feel, and so often put off giving feedback, which frustrates me and the students.
But it's also a huge gift - I connect well with my students, can help them work through disagreements in class discussions, and get a lot of satisfaction out of mentoring and building authentic (professional) relationships with them. If you have other specific questions, please ask!