A few of the education issues:
Things are a little screwy in this period. There's no degree granting institution that will let someone bum around for 8 years "studying" classics like Oxbridge. The legitimate degree granting schools were: Law, Medicine, Normal (teaching), and Polytechnic (which pretty much put you into the army). The university existed, with Department of Sciences and Department of Arts and Letters, but these are not institutions in which you enroll, choose a course of study, and get a degree.
The only way you can bum around and be a student at a government-supported institution (and all formal education at this time is government-supported) is to study law. The law school doesn't care how many times you take or don't take exams. The medical school cares a lot and it's very hard to get into. You pretty much cannot screw up at the Normal School - it's as regimented as the Polytechnique, really.
However: there are private classes. You won't get a degree, but there are private teachers that do extra medical subjects or med school prep (the collèges royaux were terrible at science education and it was common for an interested young man to do a year of med school prep before applying). Art students studied with a master, not through the Ecole des Beaux Arts. I haven't yet figured out the other ways in which you could socially still be considered a student, but I rather suspect there are.
the bigger question is actually not how Bahorel is still pretending to be a student after 11 years of not becoming a lawyer, but how Marius afforded the exam fees to finish his education. He probably could have stopped going to class entirely but so long as he expressed a vague intention of doing something next semester (always next semester), he'd probably still be able to call himself a student.
As for upheavals/conflicts/events that might overthrow a person entirely, try some scrolling through my timeline of events
from 1800 to 1833. I add to it as I find events that are even vaguely interesting, so it has a wide variety, from murders that took the country by storm to weather information to basic political changes through this era. Depending on your dates, 1816 and 1817 were awful, awful years, where the country was still occupied, political machinations were all over the place, and even the weather seemed to have conspired to keep everyone down (thanks to a volcanic explosion in Indonesia in 1815). But there might be something in there that will help you - a big chunk of those entries is wiki-able and the rest should be able to be searched for through Google Books.
What kind of literature and what kind of life is the same question. - Tom Stoppard