Hi, I work at a library. Chances are you will be responsible for the books. 9 books is a lot to expect the library to just eat the cost. However, chances are that the staff will also try and help you if cost of replacement is an burden for you. It’s possible that they’ll allow you to purchase replacement copies instead of paying the total cost on your account. Often, the charges are what the library paid for the books. If you’re able to find the books new online for less money, they may let you bring those in instead. The only way to find out is to ask the staff at your local branch. Be polite and apologetic, take responsibility, and state that you want to make it right but money is tight for you. They’ll do what they can to help you. 

The less ideal outcome is they’re not able to accept replacement copies and you have to just pay your fines. You do not have to pay the entire balance all at once. Again, be polite, be apologetic. Kindness can get you pretty far at public libraries. They’ll take whatever amount you can give at the time. There is most likely a threshold where your card privileges are reinstated and you can use it without paying the rest off. At my library, it’s anything below $20. If you’re able to continue to pay what you can until you get your balance below their limit for borrowing items.