Yes, you should have a contract between yourself and your renter. If they don't have one, then do the research and provide him with one that you are both comfortable with. If they don't want to do a contract, then you would need to consider that as a riskier situation.
There are plenty of rental contract examples on this site, do a search for Rental agreement and you'll find them and you can use them as is, or customize for your situation.
Good Luck