A 2010 CAAD9 in size 52 has an ETT of 53.5cm. According to CompFitCalc and your measurements that may be a bit on the large size but doable. I have a CAAD10 that exceeds my CompFitCalc recommendation for ETT and wish that it was one size smaller, but still ride the heck out of it with a shorter stem. My primary road bike has a 1.5cm shorter ETT and fits perfectly. We are all different obviously, but in the future I will lean toward slightly smaller than slightly bigger for a road bike. Can you test ride both a 52 and 50? If so, pay particular attention to how comfortable you are with the drop of the handlebar. My preference for go fast as I can 35 mile club rides is to have more drop. For 80 to 100 mile rides I prefer less drop.