9v oscillator circuit that produces a frequency of 500 Hz
First -- not bad for someone who &quot;doesn't know what they're doing&quot;.  Hang on to that, because I do have some critiques.
It looks like you're trying to trim the frequency with the pot at R1.  This is probably a bad idea -- if you need more precision than you can get out of a 555, then rather than trying to trim the frequency, you should find something with better precision.
If you are going to trim the frequency, then you don't need to call out an oddball capacitor value, so C1 can be 0.1uF.
I'm not sure what you're trying to do with the LC filter at the output of the thing, but you usually don't want to try to drive a coil with a logic output.  Moreover, it's going to be hard to find a coil with that high an inductance.  Unless you have some in hand, or have concrete plans on how to build it, find another way.