Would someone be able to scan my apple card while in my pocket?

If they were within an inch of your pocket, possibly. But, as the code changes each time, they couldn’t do anything with it.

No, Apple Card is an all metal construction (titanium) and is not capable of using NFC. An antenna and coil cannot be embedded in the metal. It interferes with the NFC signal. Notice that your titanium card does not have the Tap-To-Pay symbol. It does not contain the NFC chip or antenna.

Most (all?) other metal cards are actually a composite of metal outer layers and an inner layer of a polymer composite that contains the NFC coil and antenna.