Can Honda repossess my newly bought car even if they made a mistake?

This past Monday I bought 2019 Civic through the college/grad program. Filled all the paper work, got qualified, made a down payment, and sent in the four requirements. However, yesterday I get a call saying one of my requirements wasn't right (their fault not mines). They needed something to prove that I'm graduating grad school in 6 months and need it fast. I go to Webster and they don't really have a form of such so I thought I get a transcript. It'll take a week or a lol over to get it though. Will they try to repossess my car if I don't hand it to them?

No, of course they won't repossess your car in under a week. Just tell them what's happening. You're in college, act like a grown up.

I don't know what or who webster is.

Did you say you were in grad school? An MA or MS candidate should figure this out by himself. There's no form likely required. A statement from the school should be sufficient. Fail.

Congrats on the new ride and upcoming graduation. Sure buying a new car can be stressful and have problems.
There would be no way they would repo your car, unless this went on for say 2+ months and you did not make any payments.
But that being said, you need to deal with it directly, and keep are written record of each phone call, date, time person, etc. Also try to get a single point of contact, deal with only one person. Getting random customer service reps on each call will most like not work as they will not follow up on the problem. You need to follow up on this like daily or at least every other day.

The key is to make them say what they want, it sounds like you are surmising what they want. What is proof of future graduation. A transcript shows what classes you have taken, and most likely will not include current courses. The lender should have a form that says, program start date, required hours to graduate, completed hours, hours being taken this semester, based on maintaining current courses the expected graduation date is MONTH DAY 2019. Then that letter would be signed by the deans office. This is just a total guess on my part, or maybe if you simply note all this down and tell them these details that is enough for them.
Back to main point, they need to tell you what they want and what is normally done for that part of the loan requirement.
Best of luck.

Get a LETTER from your school. Are you this dense? You're in grad school and don't know how to satisfy a simple request?