Most of those brushed 550 motors are mainly used for industrial purposes. The 7.2v stamp on the motor refers to the voltage which life and performance are at best.(give/take relationship) Feeding it 9.6v nominal increases performance at a loss of reliability/life.

All the 700 motors that we have used in the past are 8.4v -12v rated. I used the 700 8.4v motor and ran 14.4v through it for many seasons.

As for an esc any 40A Brushed ESC will work well. The proboat esc is cheap and will work. Make certain it is waterproof.

Ryan