So this problem is far from unique to Juiced. You can search and find this complaint in many ebikes with single chainrings. Its a problem found on many bikes with a single front chainring that has no derailleur. The MTB community recognized this a while back as 1X drivetrains became popular. The common solutions there: a chainguide providing both tension and alignment to the chainring; and using rear derailleurs with a "clutch" that increases chain tension. Unfortunately clutch type derailleurs are only available with 10spd or greater rear cassettes. Converting to a 10spd is possible on a CCS/X but you need to change the chain, derailleur, cassette, and shifter. Gets kinda pricey.
As others have said, a narrow wide chainring can help, so can a chainguide, so can shortening the stock chain. I put a cheap ~$12 chainguide on my CCS the day I got it thanks to this site and knowing about the issue, (haven't done anything else). I only had a couple of drops until my first chain wore out at around 5000 miles and started dropping constantly. The new chain is shorter at 116 links, and I have not had any drops with the new one.