Your differential amplifier needs a dual-polarity supply. Because the 3rd opamp will have a negative output voltage if one input is positive. It cannot have a negative output without having a negative supply. So the output is saturated at 0V in your circuit.
Or you could bias one input at half the supply voltage (+4.5V) then when the other input is at +0.41V above 4.5V the output will be 2.2V lower than the 4.5V. If the other input is 0.41V lower than 4.5V then the output will be 2.2V higher than the 4.5V.