Can others access the apple wallet?

No. Your apple Wallet is on your device and added credit cards and other payment methods are tied to your Apple ID. Unless someone has access to your Apple ID, they cannot access your wallet.

However, payment methods added to Apple Wallet can be used for iTunes & App Stores, in that case if a payment method in Wallet is being used as the first payment method for the iTunes and App stores and you are the Family Organizer in Family sharing it will be charged whenever a member of the Family Sharing group initiates a purchase unless they have Gift Card credit balance. In which case it will charge that before charging the family Organizer’s payment method.