Please excuse my ignorance,I'm fairly new to this field. So with OpenWifi, will I have control as to what packets I would like to send over the air? So for example, can I construct a specific packet using OpenWifi and then send them over the air over a specific channel (say channel 11, 2.4 Ghz)?

A bit longer answer: Basically Linux gives packet to our driver, and then our driver gives the packet to our FPGA for further processing (queuing, modulation, CSMA, etc). So you can compose your packet in the driver or anywhere else that can communicate with the driver, then instruct the FPGA to send your packet at any frequency 70M~6GHz.

It will be very worth to read the README and project document word by word on the github: https://github.com/open-sdr/openwifi . I believe you can already find answers of more questions there.