My son is 9 weeks old and just came down with a cough. is there anything safe over-the-counter that i can give him?

No: The best thing to do is to check with his doctor. Since he is so young, you can't easily tell what the cause is. Most cough and cold meds are not approved for children under 4 years old- they aren't effective and have side effects. Clean your baby's nose with saline drops and the bulb syringe. Use a cool mist humidifier. Make sure he is drinking enough fluid.