The title is sort of a tl;dr, perhaps.
Background: I've been working a job as a software developer for the past nine months, which also happens to be my first full-time software gig. The job basically entails writing line-of-business software (in C#), and maintaining the undocumented clusterfuck that is our internal / backend systems. I'm 24, and I've interned as a developer once before (writing embedded software, which was my study in college).
Over these nine months, I've just lost enthusiasm for my work. I spent a fair amount of the time reverse engineering the aforementioned internal systems so that at least someone knew how they worked, and tend to handle the maintenance work for them (insofar that any can be done, completely random side effects are the norm here). I've tried to lobby for a replacement for said systems, but no such luck, and we lack the manpower to even comtemplate writing our own replacement (think CRM/ERP system). Seeing a help desk ticket regarding this stuff is usually instant demotivation.
The other stuff I work on is fairly benign when it comes to weirdness, but I can't seem to find any real interest in it. The problems simply aren't difficult, just drudgery. I've tried to get my hands on a more complex project, but everything my manager has been able to get me has gotten cancelled shortly thereafter due to no funding, or no time to implement it, etc. I get to do a variety of tasks since I handle some of the IT responsibility on top of maintenance and development, but it's awfully rare that I get to develop anything new and/or interesting.
I've tried to make up for it in the past by coding at home, but I rarely find that I want to fool with it after 8+ hours of grinding away at something for work. I have friends who feel the opposite on the matter, but it doesn't seem to motivate me in the same way.
Long story short, work is bringing me down in a bad way, and I'm not sure if there's something I can do to alleviate the feelings I've got for it at this point, or what other options I have.