According to the invention, there is provided a novel soybean variety designated XB39U09. This invention thus relates to the seeds of soybean variety XB39U09, to the plants of soybean XB39U09 to plant parts of soybean variety XB39U09 and to methods for producing a soybean plant produced by crossing plants of the soybean variety XB39U09 with another soybean plant, using XB39U09 as either the male or the female parent.