Well water can sometimes not be suitable for fish. Have you had the water tested to make sure it is appropriate for fish? Aeration is a good thing, particularly in a warm climate like FL. Oaks produce tannins, placing them in the water can leach the tannins into the water. Depending on just how much oak limb you have in your pond, can affect water quality. Usually a lowering of the pH and causing the water to be coffee colored. The use of the concrete scrap may actually help counteract that affect though. Concrete has the opposite affect raising the pH of water. It is hard to tell what the affect of those two items may be on the water quality...
The number of sunfish(BG and RES) you've already stocked is enough to establish your fishery. You won't need to add any more IMO. What size where the BG and RES when you stocked them? What species of minnow did you stock? Fathead minnows, golden shiners or another species?
If you are trying to grow mostly nice sized bass, I would not stock any crappie. Crappie are very difficult to manage in ponds and often lead to stunted masses of crappie with all other species suffering. You can consider adding the crawfish when you can find some to purchase. When you mention perch, are you referring to the other common name for crappies, speckled perch or yellow perch, white perch or the other common name for sunfish?
If you are looking to grow nice bass, I would probably stock closer to 50 bass rather than 75. Since you are in FL, you have the option of stocking FL LMB. I am not sure just how far north you are, but you can also consider using F1 LMB as well. If you're too far south, I'd stick with pure FL LMB as they are native to that part of FL. Stocking them this upcoming fall or winter would work well if you stocked 2"-4" sunfish this month. If they were adult sunfish, I'd probably stock them a little earlier.
Had the fish been feeding the first few days after stocking and then stopped feeding? Have you received a recent cold front that has dramatically reduced the air and subsequently the water temperature? There is a unique smell you can sometimes smell when particularly sunfish spawn. However, this is not the time of year sunfish or bass typically spawn in north FL. And unless you stocked adult fish, your fish wouldn't be able to spawn yet.
With the large number of fish you just stocked some mortality is to be expected. 9 fish is not an overly high number. Continue to monitor your pond but nothing sounds too overly concerning IMO. Let's see what some of the other members have to say.
