There are many routes you could take this with different membership plugins or subscription based plugins which would accomplish what you are looking to do. However, the best starting point for you is probably using an LMS (Learning Management System) plugin or theme. An LMS will provide everything you need out of the box and will be scalable for your future needs as you develop more courses, integrate quizzing or surveys, award badges or certificates, etc.

The LMS will integrate the membership or subscription tools you'd find in those plugins with all the other tools you'll need to create your coaching course.

Let me know if you want to dive in more.