First let me say that I am blown away by the number of responses (mostly positive) to my mistake, and the amount of well thought out advice given. I really didn't expect this level of support.
I'll try to address a couple things brought up here. The 9mm being reloaded included both 115 and 124 grain FMJ bullets which were loaded with CFE pistol powder. When I first saw the problem the powder load was more than the maximum listed in the Hodgdon table so no question those rounds need to come apart.
When I talked about weighing the rounds to try and determine whether they needed to come apart it's because I'm not sure exactly when the problem started. I've only been reloading since the beginning of the year but have changed the setting on the powder measure a number of times as I switched between 9mm and 223 loading. I know for sure that at first I had checked the zero on the scale as well as looked up the VMD setting to double check, and we've been shooting those rounds without any indication of a problem.
About a month ago I bought a second powder measure so I could keep one set up for 9mm and the other for 223 as those are the only two calibers I reload at this point. Somewhere along the line I set the 9mm measure up going by the charge weight showing on my Lee balance scale which unknown to me was not correctly zeroed. And I didn't double check the VMD which would have shown the problem. Big mistake on my part, I know that now. I just don't know exactly when this happened.
I have my reloads pretty much lined up by chronological order so working backwards I should be able to find out where the problem started and loads done before that should be ok. I have already separated those earlier loads by headstamp and made up check rounds with the correct charges. My thinking is that by comparing the suspect loaded rounds to what I know to be correctly loaded ones I should be able to tell if they are good. If I don't think I am getting clear evidence of which are good and which are bad I will pull them all.
I've read opinions advocating both the collet puller and inertial puller as being best. I have an inertial puller and have ordered a collet puller which I got today but unfortunately the proper collet for it isn't scheduled for delivery till Wednesday. So I can't compare them yet.
I started pulling ones I know are bad yesterday with the inertial puller and it's not as bad as I thought it would be. I was hitting it on the corner of my bench which has an angle iron frame and wood top but it took 10-15 hits to dislodge a bullet. I then put a 25 lb plate from my barbell set on the table and hit the hammer on that which usually did the job in 3 strikes, not so bad. The main problem is that I lose powder out the top on every round. Not a lot, but the collet puller would in theory preserve all the powder making it the better option, perhaps.
At any rate I pulled about 150 bullets yesterday and it went faster than I would have thought. If I have to do it that way it's definitely possible.
I actually have more like 2k rounds loaded but I'm assuming the ones loaded last month are ok, but they all will be weight checked. As previously mentioned they have been shooting without problem and I'm 99% sure they are good, the weight check is just because I'm now a little paranoid.
Going forward since I bought a digital scale and still have the balance beam as well as fully intending to watch the VMD on the powder measure I will have a triple check on anything I do. That should be sufficient.
Any new skill has a learning curve. I hope that I am now over the hump on this one, and future mistakes will be smaller ones.