My cat cries every time I leave the house and my neighbor says it goes on for hours.

Eight months in with it getting worse rather than better is important information. Some cats do settle with time. The fact that he has not, and that it is escalating, tells you that he has not found a way to regulate on his own and that he needs active support rather than more time.

What you are describing is genuine separation-related distress, not just a cat being vocal for attention. The key difference is that he is not doing this to train you. He is doing it because he does not have the internal resources to manage the experience of being alone. That is not a character flaw. It is a skill that can be built, but it has to be built deliberately.

The approach that works is not about making departures less obvious or sneaking out, which many people try. It is about gradually teaching him that your absence is safe and temporary, through very short, structured absences that never reach the point of distress, repeated many times until his nervous system learns a different pattern. It is slow work but it does produce real change. I have a page on separation anxiety on the site that goes into this in detail. If you want to work through a plan specific to him and your schedule, the Work With Me assessment is the right place to start because the details of his day, his history, and your routine matter a lot for building something that will actually work for both of you.