Welcome to VAF Cyrano de Bergerac. It is possible to fly with an open canopy but it depends on the type of canopy. A slider canopy is really the only type that is really practical and only if it has well engineered stops that prevent the canopy sliding all the way back. At the speeds an RV-9 is comfortable at, a partially open canopy is more of a liability than a feature. In the hot climates of Brazil if the outside temperature on the ground is above 38?C then it is better to fly with the canopy closed. Remember, a lot of stuff that is not tied down (maps, notes, log books etc) can go overboard because of the suction effect.
Best of luck and I hope you get some more useful responses to your question as a first time poster without having to search the archives.