if you received 12.000 credits you are an early backer, so untill the 26th i think of november you get LTI on any ship you buy

Also i am a total fanboy so yea i am rather up-to-date
As for your question, if you want to spend it, at this time it seems the workbench is best, because that is going to have actual use ingame. That would leave you 2k and you can spend it on whatever you want in your hangar
Personally i am still hanging on to my UEC. As soon as the dogfight module is out we should be able to earn a couple of them so i'm gonna see if i van get a buggy else i will also get the workbench. When the PU (public universe) is out you can earn them ingame. There also i a limit to how much UEC you can buy per day or per week (not sure)
this is to prevent pay to win when the PU is live