Can I work in a job during the process of becoming an officer?

There is nothing in the regulations that prohibit you from having a job while going through the application process. Once you are accepted into a commissioning program, you can work right up until the day before you report to training if you want to.

Definitely, I would recommend that. Stay productive, keep working and when they cut your orders give your employer a 2-week notice. It will definitely help time pass. I kept working at my civilian hospital a month prior to my report date cause the process for me to go active duty took 13 months.

There are several paths to a commission, and they all differ dramatically. Since it seems you'll have a degree before applying... sounds like OCS is your ticket. As I recall, OCS lasts about twelve weeks (don't know if they do roll-backs, etc.) and is "in residence" training. Perhaps the simplest way to explain that is that you'll be living that training 24/7. I don't know if OCS candidates get weekends, but would imagine they get some "time off" base... though I doubt it would be enough to hold down a second job (or that you'd have the energy/interest in doing so). Obviously, you'd be free to continue to pursue employment while you apply.