I work 9 hours a day. I started attending a masters that assumes you work 8 hours so lessons start one hour earlier than I'm supposed to clock out. I told the boss, and he was MAD. Even though I told him I'm taking the job cause I wanna do a post-grad.

What do I do now.

Tell your boss he’s a fuckwit

Soft quitting

Get up an hour early for a week until your fuckwit boss loses attention.

What was the agreement?

How strict are your working hours?

If the agreement was "OK, take that class as long as it doesn't interfere with work, we assume you'll make it work" and you missed the fact that the classes start too early that's your mistake.

But maybe it's an easy fix by just starting work one hour early.

Fuck your job.
(I’ll skip the rest)

Usually I'm all for saying you need to hold your own against arsehole managers, but in this case did you clear it with him before you took the course? If not and your contractually agreed working hours are 9 hours, I can see why he's annoyed.

Your options are essentially to see if you can catch up on the first hour a bit later on, chat with your boss and see if you can work something out around working hours, or quit and find a new job.

@AlmondSauce he knew full well I'd take a postgraduate degree. You see, in my country there's mandatory military service, which I still haven't fulfilled, and one of the ways to delay it is by being in a state sponsored education program, like a bachelor's or master's. So if I got the job and didn't enroll in post-grad, I'd have to leave my job to serve. Our agreement relied solely on the fact that I'd enroll in a postgrad so that I could legally continue to work.

UPDATE: He proposed that I send him the days I have early lessons a month in advance, so that on those days I can start an hour earlier and leave an hour earlier as well. At least it's reasonable. Though I still don't get the whole fixation on working hours, we've got flexible hours anyway, people start and leave half an hour later or earlier respectively. What can I say, all I am is a remote underling worker anyway.

@aggelalex the fixation on when you leave work is weird indeed. Companies I've worked for assume not everyone might be available after 4PM, as some start very early in the morning and some have to go pick up kids from school etc. So most meetings are booked earlier, and the end of the day is usually reserved for working on whatever you need to do.