It is not possible to buy an ESC without a BEC. The BEC is in reality a voltage regulator that powers the brains and other electronics in the controller. The regulators used in common ESCs have adequate current rating to power an RX and several servos, thus the BEC. Cutting the red wires removes the RX and servo current drain from the ESCs regulator. This results in a very small load (~10ma) on the battery and should run the ESC for some time on a 9V battery. If you are planning on using 9V "transistor radio" battery, 1 activation of the brake at 1.5A will eat the battery's lunch. BEC current drain is the least of your worries in this application. Sounds to me like using an ESC for this application is over-kill. Would you consider an alternate design?