Absolutely! HeyMax voucher purchases (Grab, foodpanda, or any other brand) are generally processed under MCC 5311 (Department Stores), regardless of which voucher you buy — there's no voucher-specific MCC override. Based on this MCC, you'll be able to earn credit card points per your card issuer's rewards program.
Note: the final classification is determined by the card network/acquirer, so it may occasionally vary.