The molality of a saturated solution of potassium chloride at 90 degrees Celsius depends on the solubility of KCl at that temperature. Without knowing the solubility of KCl, it is not possible to determine the molality of the solution.
However, it is worth noting that the solubility of most salts, including KCl, generally increases with temperature, so a saturated solution at 90 degrees Celsius would likely have a higher molality than one at a lower temperature.