I didn't receive a 1099-INT because my interest was too low (under $10). Do I still need to claim it?

Yes ... all income should be reported no matter how small and even if no tax reporting form will be issued. Technically if you know about it you should report it since you sign the return stating that all the information on it is correct to the best of your knowledge. 

If you only had one account that paid $9 in interest  then this will probably never be questioned by the IRS  however if you had 10 accounts with $9 each they would miss the $99 because that amount is reported to them even if a tax form is not required to be issued.  

That does make sense, but it sure is hard to attach a form when there isn't one available.  Since I don't have 10 bank accounts (or even two), and the bank didn't see fit to issue me a 1099, it did make it a bit harder to know what to do. 

I ended up entering it manually, as my bank isn't one on the recognized list, but... what a pain in the neck! Not that taxes were ever meant to be anything but...