In this case humbling themselves implies that they would not eat any food. This can be stated clearly. Alternate translation: "you must humble yourselves and eat nothing" (See: [[rc://en/ta/man/jit/figs-explicit]])
This refers to the seventh month of the Hebrew calendar. The ninth day is near the end of September on Western calendars. This can be made explicit. Alternate translation: "the ninth day of the seventh month" (See: [[rc://en/ta/man/jit/figs-explicit]])