What 12V cigarette lighter / USB charger is best and what cord is best for speed for a Samsung Note 9?
Could you give the specifications of the input (power, socket) of that device?
Would be easier for the “helpers” here to have these without searching around a lot.
Note 9 supports 15w fast charging.
So go with a USBC PowerDrive offering 18w output and that will sort you out and charge to 50% in about 30 mins.
As for cable, pretty much any Anker USBC to USBC will work for you.
Just try and avoid getting a cable longer than is required.