"Library" What does the librarian imply when she tells the man to return at nine o’clock?

Narrator: Listen to part of a conversation between a student and a librarian.
Librarian: Hi, how can I help you?
Student: Hi, I’m looking for some material on reserve for Business 210.  Q35
Librarian: Okay. Well, who’s the professor? You see, we keep the files under the professor’s name
    because there are a couple of sections and the requirements are a little different...
Student: Oh, okay. It’s, uh, Dr. Parsons.
Librarian: Umhum. Parsons? I don’t see any books...
Student: I think it’s a DVD.
Librarian: Oh, yes. Here it is... Oh, wait, actually, there are two of them. But that’s all right. Now
    all I need is your student ID.
Student: No problem.
Librarian: There you go. Now, these will be due back at the desk in two hours.
Student: Two hours? But that won’t even give me time to go home and...
Librarian: Oh, you can’t leave the library with reserve materials. You have to use them here. But
    we have some DVD players in the booths behind the reference section. I think there are
    several free now.
Student: But I have to take notes and, uh, uh, I don’t think I can get everything done in two hours.
Librarian: Well, you can’t take materials out again until someone else has used them because the
    professor only left one copy of each. Sorry. Look, maybe two hours will be enough.
Student: I don’t think so. These are case studies, and we’re supposed to be able to discuss  Q36
    them.
Librarian: Oh, I see. Well, when do you have class?
Student: Tomorrow morning. I know I should have come in earlier, but this isn’t my only class. I
    had an exam earlier today, and I was just waiting to get that out of the way.
Librarian: I see. Well, look, why don’t you...
Student: Isn’t there any way to get an exception to the policy?
Librarian: I’m afraid not.
Student: Oh. Okay then, let me just check out one of the DVDs. That way, if I finish it, I can check
    out the other one for two hours, right? Librarian:Sure. That’s perfectly fine. And, here’s a thought. I don’t know if it wilt work for you since  Q37
    you have a morning class, but if you checkout reserve material less than two hours
    before the library closes, then you can have it overnight...   Q38
Student: Overnight?
Librarian: Yes, but you have to have it back when the library opens the next day and...
Student: But I could do that. Oh, I’m sorry, you were going to say...
Librarian: Well, if you don’t return the material to the reserve desk when the library opens, then
    there’s a ten-dollar fine for the first hour and a five-dollar fine for every hour after that...
    that it’s late, I mean. The usual fee is one dollar for every hour but when it’s an
    overnight...
Student: Ouch.
Librarian: It’s a stiff fine because we need students to take the privilege seriously. Otherwise,
    other students who need to use the reserve materials wouldn’t have access to them.
Student: Oh, I understand.
Librarian: And another thing. Sometimes more than one person is trying to use the overnight
    privilege so... so sometimes when you wait until the end of the day...
Student: Oh. And there isn’t any way to put your name on a list or anything?
Librarian: No, not really. It’s first come, first served.
Student: Okay. Okay. Then, I think I’ll go ahead and take the one DVD out now because I can
    still try to get the second one tonight overnight, can’t I?
Librarian: Sure. I tell you what, Come back a little before nine.  Q39
Student: Okay, Will you be here? I mean, I’drather come back to you.
Librarian: I’ll be here until the library closes.
Student: Well, then.
Librarian: Do you still want to take out one of the DVDs?
Student: Yeah. I might as well get one of them out of the way so I’ll only have one left to watch.
Librarian: Wait a minute. Your ID.
Student: Oh, I’m sorry, I thought I showed it to you.
Librarian: You did, but I need to keep it here at the desk until you return the materials.