2009 Plus Size Prom Dress Trends. The prom dress styles for plus size prom dresses that are popular for 2009 are based off the red carpet. These curvy celebrities looked great on the red carpet and they set the styles and trends for 2009 plus size gowns. The key to finding the perfect plus size gown is by playing up your features that are most falttering, it could be your shoulders, arms, bust line or whatever body part you think looks the best. Look below to see the popular styles.