Can I set a curfew for the Student?

Students appreciate flexibility. You can however set out rules regarding communicating about when the Student will be coming home.

You are sharing your home and you are responsible for setting and communicating the rules of your house.  Remember that you are usually hosting young adults and they will appreciate flexibility as they explore this new place and adventure. Try to balance your needs and expectations with theirs as you work together to agree to house rules.  Ensure your house rules contain information regarding when a Student needs to contact you to let you know they won't be home for dinner, or for the night. You should also include information about being quiet when returning home late etc. 

With high school student and younger, you may set a reasonable curfew and discuss it with your student when you discuss your house rules.  There are usually local curfew laws in place, which students are also expected to abide by.