My 9 month old just started using a nebulizer and he seems to coughing more and I wonder if is this normal?

yes, my son had a horrible cough for over a month and it would make him puke. They finally figured out that it was asthma & Gastroesophageal reflux disease (GERD. But yes the nebulizer will make your child cough more because it breaks up all the stuff in his lungs. Its normal for them to puke & cough up stuff sometimes, especially if they have asthma.