Yes, you can add a small transistor such as an NPN 2N2222 to amplify the photocell current. Connect the photo cell between the +9V and the base of the transistor. Connect the emitter of the transistor to the minus battery terminal. Connect the lamp between the +9V and the transistor's collector.
What is the lamp's current? If the lamp is an LED than you will need a resistor of the appropriate size in series with the LED to limit the current to the desired value.