hey,
Working at first year university is always tough -- no matter what program --, because there is definitely an adjustment phase... but don't be too discouraged. I have friends who were able to work, not in iSci specifically, but in other demanding programs.
You can definitely make it work it in iSci, and i'm considering working part-time myself during second year. Though, I would only recommend it if working is necessary for your financial situation, or if the work experience is important to you.
You will likely have to sacrifice time for volunteering, time for studying, time for clubs, time for partying, etc... but there is, no question, enough free time available to work if you're willing to sacrifice some of those things.
There are lots of jobs, not only on campus, but off campus in Westdale, Dundas area, etc, that are used to accepting students, and are often flexible with times, I would look into the options for sure if you are interested, something might be able to suit your schedule.