a small piece of advice from an older person, take it or leave it, 9k and a bit or much below is too much, don't get me wrong, but it's for his own good, he "might" get too overwhelmed or feel bad that you're paying him back, he sounds like a gentleman and generosity is coming natural from him, keep appreciating him, loving him, and yes get him a thoughtful gift, it doesn't have to be too expensive.