Pardon me if this sounds naive, but I'm slightly confused as to how recreational marijuana is legal in 9 states but the DEA still heavily controls cannabidiol as if it were still illegal?
The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
This has been an issue since the 1780s, so it will take more than a couple of sentences to give the whole rundown but it's like this. A few states are saying "we have explicitly made marijuana legal for adult consumption, and since the Federal Constitution doesn't forbid this, it's legal," and the federal government is saying, "um, I don't think so. Cannabis is a schedule 1 drug that is regulated by the DEA, and it can't be made legal. And we intend to enforce this with the DEA."
So every once in a while, the DEA come in and shake up a cannabis operation (they raid the grow house or the dispensary or sometimes [rarely now] raid patients' homes) that is legal at the state level but federally illegal and there's a whole jurisdictional issue. The local police used to cooperate with the DEA in decades past, but have since told them to get bent. Now there aren't enough federal agents to deal with this, and a lot of local police forces have realized that cannabis is really not a big deal, so sometimes these things get enforced and sometimes they don't.
So we're in a gray area right now, where you can purchase cannabis legally or medically in quite a few states, but it's still illegal at the federal level. Apart from selective enforcement of this being scary, this opens up weird issues for seemingly law-abiding citizens: Since cannabis is a schedule 1 drug, using it precludes you from purchasing a gun legally at the federal level. So a law abiding citizen can easily unknowingly put themselves into a situation where they're breaking federal law even though they're abiding state laws.
If you want to see how ridiculous DEA drug scheduling is, check out this page: https://www.dea.gov/drug-scheduling