No, he can’t. Biden isn’t emperor, and the DEA is an independent agency. Presidents don’t just get to tell the DEA what to do. You clearly don’t understand how our government works. What he can do is have the Dept. of Health and Human Services order a review of marijuana’s scheduling, which he has done.
Now, the FDA has already recommended changing the scheduling, and the DEA is currently considering it, so the process is actually underway.