Note that the op-amp can't boost the voltage, above the supply voltage. It will need to be powered from at least 10V, if it has a rail-to-rail output or at least 12V if not.
The simplest power supply is a couple of 9V batteries in series, for a single supply op-amp, such as the LM358 or LM321. A small 12V battery such as the A23 battery could be used with a low power, rail-to-rail OPA705 op-amp is probably the most compact solution, but the resistor values should be high, to keep power consumption to a minimum. Another option is running the LM358 or LM321 from a charge pump, such as the ICL7660 and 9V battery.