Maybe his aversion to a "professional business plan" is a legitimate distrust of paperwork and bureaucracy. It's hard to say.

Does it really matter if he's typical of some clump of humanity or other? What matters is can the two of you make plans and communicate.

If his style is different from yours, can you work with that? It's normal for 2 people to bring different skill sets to the table.

If you're asking Clarity.fm if your business partner is unprofessional, then clearly the 2 of you CANNOT work together.