I'm mostly wondering if it's even possible to do this or if i need additional hardware outside the Arduino and the Xbee Shield from SparkFun to be able to communicate with the Xbee directly so that I can set the baud rate.
Yes, it is possible. No, you don't need more hardware. In fact, you need less hardware. You need to remove the ATMega328 chip from the Arduino while you are doing this. Be sure to keep track of which way it is installed, so you can reinstall it the same way.
That's a hassle, so getting a USB Explorer is a good idea.