Question: How old are Dean and Sam in season 9?
Answer: Dean is 33 and Sam is 29 around season 9.
Answer: Early 30's. The flashback shows them 22 years earlier when their dad says "Dean take your brother and go." Dean looks to be 5 and Sam is just a baby.
Answer: There are 4 years between Sam and Dean so Dean was 4 or 4 1/2 when he took Sam out of the house. Sam was 6 months.