The 9 looks like it's in two pieces. Those are very good, sharp pictures. But look what you're thinking are two impressions of the 9. Are the 9s really that thin? Get another 1986-D, and look at that 9. These 9s are half that size. They're cut in two, right down the middle, from the strike. The "top" 9 should be intact, matching the 9 on any 1986-D, but it's not.
This is what the date should look like. All the numerals are thin and dainty. Looks to me like the high points took on some wear making it look doubled.
Thanks Eddie. Good thoughts. I wonder though how just the 9 (and maybe the 8 to a lesser extent) can be double struck without more of the coin being impacted? BTW, I used a Opti-TekScope for the pics. I diffused the light to reduce glare.
I wish everybody had pictures like that. They made this easy. My best suggestion is to go on YouTube and bring up a video on the minting of cents. These are hardly done with cookie-cutter precision. When a coin gets loose from its collar for all the banging virtually anything can happen when struck with those dies. That coin moved a little, hopped, slid when those dies grabbed it, and that's what's showing. In die doubling, it's the actual die that's doubled. In strike doubling, what happened on your coin, the coin wasn't sitting still. It was loose, and it didn't accept the strike cleanly for it.
To have wear only on the high points of the date? Yes, It is not a doubled die though. There is a form of worthless doubling that the devices appear to have a crease in the middle of them. I believe it is a form of split plate doubling, or from a gassy planchet. @paddyman98
