Don't do parallel battery connections. Bad things can happen especially if one battery is partially discharged.
You actually have to model a battery as an ideal voltage source and a series resistor. The series resistor in the model limits the short circuit current.
Current is the same EVERYWHERE in a series circuit. In your parallel example and if and only if the batteries are the same and have the same internal resistance then each will supply 1/2 the current. If they aren't then one battery may be trying to charge the other or the current will current divide between the two batteries, In other words, one battery might get too hot leak and do other nasty things.
Kircoff's current law states that I1+I2= 1 Amp Basically, only in the movies will the batteries deliver equal currents. In practice, they will not.
A 9 ohm load will need I = 18/9 or 2 Amps like you said. Each battery will supply 9 V at 2 A. Kirkoffs law states that 9 9V+9V = 2 Amps*R