I am framing a dropped ceiling below an existing floor assembly which is 3" off level over 20' +/-. The dropped ceiling members are 2x6's with a span of 9' attached to ledgers using 3" screws. Dropped ceiling will only support new 5/8" blue board. Question: are joist hangers needed at each end of the Dropped 2x6's according to IRC regulations

For the safety of the ceiling, it would be desirable to install some hangers for the beams at each end of the 2x6s, according to IRC regulations. I always install beam hangers so that everything is in order and quality. But for that, you need both quality screws and hangers for beams. Many people buy low-quality screws and hangers and thus leading to unfavorable situations. I had a lot of such situations, and that's why I always order from scrooz.com.au. So be careful and take and consider this.