Circuit Analysis Involving DC Motors
If it's a "brushless motor" that's running off of 9V DC, then it's a motor and a controller -- and all bets are off, because the controller could be anything.

The 5V 0.4A rating means that if you put 5V on it and load it to it's specified torque it'll pull no more than 0.4A (or if it's a brushless fan, it'll just pull around 0.4A).