Ditto the Bullet casting malady; I have about 50+ bullet moulds, mostly Lee, because I can try out a mould, and if I don't like it, I've lost nothing. If I do like it, I'll get a 6 cavity one! (That is if they make one for that design). I too have a 100lb stainless melting pot I use over a propane "fish cooker" to melt the weights/scrap and cast into ingots. Also have a Lee 20lb-IV pot, and two 10lb production pots (one has a burned out heating element and I haven't been motivated to send it back to Lee)
Regarding casting for the 9mm;
I've had very poor results from the Tumble Lube bullets in 9mm, 10mm, and so-so with the .45acp. Outstanding results with the .358" for .38spl. however.
For the 9mm, the only mould I can recommend is the 124gr TC with the single lube groove. You can still tumble lube it however.
(The 147gr RN for the .38 Super works well too, but is limited in usefulness in the 9mm But mine are fabulous in .38spl target loads- it casts at 160gr with W-W, and comes from the mould at .359")
The rear driving bands on the 9mm, 10mm/.40, and .45 tumble lube bullets aren't long enough to handle the pressures with any alloy except linotype, which is rare these days, and getting rarer. I was "gifted" recently 150lbs. It's the first I've seen since I was in grade school and toured a Newpaper's printing shop in the '60's.
For bullet alloy in the 9mm (ditto the .40/10mm) I've found wheelweight with about 2-oz of Lead Free solder (95%tin 5% antimony) added produces WONDERFUL bullets. I normally size them to .356" and lube with 50/50 alox (Lee, RCBS, or Javalina work equally well). With a "proprietary" amount of Hodgdon LongShot, I'm getting accuracy that I won't specify as I've been told I'm full of "green garden humus" as the guns won't shoot that well. But, Saturday was a week ago, I shot a registered 1480-88x in a PPC regional match with my "home brew" bullets/ammo. They (bullets/loads) have outshot all of the jacketed "premium" bullets I've tried im my S&W PPC-9 6". I will say that most of my 25yd "bench" groups are running 1-hole.
I've got several sources for wheelweight in the central Georgia area. But, I'M NOT REVEALING MY SOURCES !!!!
I go through about 300-500lbs annually, so, I'm not very forth coming with my stash! You'll have to find your own! Actually, I find that many of the sources I have gladly part with it, as a lot of the recyclers are charging the "sources" to take it off their hands. I suspect that some of the tire weight producers are starting to have a harder time getting the raw materials and are finding it preferable to "recycle" their products, hence the issue in the Houston,TX area.
We can probably eventually expect the supply of cheap lead to play out. Then we'll be in a "tight" and forced to accept EXPENSIVE ammo.
FWIW, I've found range scrap alloyed as mentioned above to work equally well to wheelweights. You might try that. The birdshot mentioned will be too soft for best bullets in the 9mm. However, with some of the LeadFree Solder added it should do ok. I get it at Lowe's and HomeDepot in the plumbing supply section. The Silver-bearing solder works OK, but you'll have to flux well and skim off the "bluish tinted" silver that work its way out of the melt. (This might be helpful if you have an "outbreak" of vampires or werewolfs, though!)
You probably won't have to size the Lee bullets, but do use the tumble lube straight as it comes. I find this best for the 9mm. For .38spl, I cut it with about 1:4 mineral spirits to lube. I just fill a new bottle to the bottom of the neck of the bottle and shake well. 4oz bottle will lube about 25,000 .38 slugs.
Good luck with your attempts at bullet casting.