Hotels in Kyoto tend to be booked up for cherry blossom viewing very early. That is not to say there won't be something open up from cancellation but chances are slim.

When I have run into problems of this sort for Kyoto, I have had some success relocating my stay to Nara. It can be as beautiful with the sakura all in bloom and the trip to Kyoto is only 45 minutes on JR or about 35 minutes on Kintetsu. You might want to search Nara in addition to Osaka.