Upvote:4
I took (pretty much) that exact trip last week at a bit later time, and didn't feel the slightest bit in danger. The metro is crowded with all kinds of normal folks. You can't beat 5 pesos for transportation that far, and it shouldn't vary much with traffic etc. You should be able to get a seat for many of the stops since the University is at the end of the line.
You could also take a taxi, of course.
The campus is huge, make sure you know how to get to your transportation.
If you want to increase comfort and reduce risk, you can use a radio taxi from the University- it's something like 25km so maybe $15 US or so, and you may have to leave an hour or more as well at rush hour.. don't know I only used the metro.