Stop. Do not pass go. Do not go to Walmart or BestBuy unless you want to pay a lot more than what you would pay on Amazon. For a Galaxy S9, you want a charger that supports Qualcomm Quick Charge 3.0 which is backwards compatible with Qualcomm Quick Charge 2.0
Fast Charge 3 will charge your phone from 0% to 100% in 2 hours. Go to Amazon and search for "Galaxy S9 fast car charger". You will see lots of options at about $10. Pick one that has good reviews. One that also says that it does "adaptive fast charge" is even better. I suggest one that will charge two devices at full charging rate.
If you can find one at the same price point at Walmart of BestBuy, go for it.
@JASFLALMT wrote:
Yeah, I googled it after I asked. I still need to find something by Thursday so I am going to go online to Walmart.com and Bestbuy.com to see what they have in stock.
Shopping Southeast Pennsylvania, Delaware above the canal, and South Jersey since 2008