According to the invention, there is provided a novel soybean variety designated XB15M09. This invention thus relates to the seeds of soybean variety XB15M09, to the plants of soybean XB15M09 to plant parts of soybean variety XB15M09 and to methods for producing a soybean plant produced by crossing plants of the soybean variety XB15M09 with another soybean plant, using XB15M09 as either the male or the female parent.