A one year lease is really a long-term tenant situation, not an airbnb accomodation, to my mind. Do you have a website, or any other way he can contact you outside of airbnb? Assuming that he sounds like someone you would want as a long-termer. Since he has no reviews, I'd not rent to him through airbnb- host support is terrible and you could find yourself stuck with a bad tenant and no way to remove him, or he stays and then asks airbnb for a refund. For a year-long tenant, I'd want recommendations from previous landlords, employment history, criminal record check, etc.
If I was going to rent for a year (and I have) I'd do it as a regular landlord/tenant deal with a proper rental contract, not rely on airbnb to resolve any issues that could come up.