The problem with fixing the jack is these machines are so old, nobody makes new jacks. You will need to find the power jack board to fix that; it's relatively cheap and easy to find on eBay if you search 820-0986-b. You'll also need to replace the power adapter, since that usually gets damaged when this happens. Other then this, that's all you need to fix the damaged jack.
If you choose to repair this, I'd recommend replacing the hard drive with a CF card and a CF->IDE adapter. The original hard drives in these machines are at least 20 years old and are bound to die any day at this point. While I linked to a 32GB card because of the $8 cost differential, a 16GB card should be sufficient for OS9 and the games your daughter plays. You will need to reload the OS, but images can be found on sites that archive OS installers like WinWorld.
While you can fix this, you may find it's cheaper to purchase a newer model like the PowerBook G4 Aluminum. These can't run OS9 natively, but you can run Panther (10.3), which does not need Classic Mode. However, if you choose to run Tiger (10.4), you will need to install Classic Mode yourself. With that being said, the TiBook runs OS9 natively but the problem with these is the stock hinges are known to fail (Titanium is bad for moving parts). The iBook doesn't have this problem, but the hard drive is difficult to replace. However, they are cheaper then a PowerBook.