I am on iOS 10.2 (Jailbroken, iPad Air 2) and I recently installed a bad tweak, it put me into a boot loop in which I got out of, but when I enter safe mode I can't go into cydia and un-install it because cydia keeps crashing, I try to enter yalu102 app and re-jailbreak but when it "successfully jailbreaks" it goes back into a boot loop because of the bad tweak I installed.
Are you sure it's a boot loop and not a respring loop? You say you "got out of it" suggests it's the latter. Cydia crashing means you're not in Safe Mode but rather in an unjailbroken state. Whilst tapping go in yalu102, hold volume up until the device resprings to try entering No Substrate Mode. From there you should be able to open Cydia.