I have a 9-8 job, live alone and want to prepare for University/other job. Is this even possible?

I work as a clerk in a PSB. We have to work basically from 9:30 to around 8:00. Commutation takes a total of 30 minutes to and from my office. Have to cook on my own, do dishes on my own. All these eat most of my 24 hours, leaving me with 1-2 hours of free time. Can I crack IGNOU exam or any other job exam at this rate? I thought of decreasing my time sleeping for studying (12:00am to 7am) but I fear I might become drowsy at work or during the 1-2 hours free time. What should I do?