Chances are good that you don't need all that voltage. Usually, the +/-18 volts is the maximum allowable voltage on an op amp.
Unless you know the signal of interest is going to be very large, the +/- 9 volts might be enough for your purposes. For instance, a signal that gives a 2 volt output will be fine with no more than +/- four volts on the supply rails.
I use LM301 as instrumentation amplifier. I tried use +/- 9V. It is not working fine, sometimes no respon output when I change the input voltage.
If I used +/- 15V supply voltage, it's working fine. I use MAX1044 to make it portable, only use a 9V battery. The schematics is on attachment.