By the time you go through passport control, bag claim, and have your car under your derrière it will be close to 2 pm and many restaurants in Italy don't stay open much past 2:30pm. If I were you I would hit the freeway and stop at a rest stop at an Autogrill, which are good and are always open. Rest stops on Italian freeways are full service areas with fuel stations, restaurant facilities, shopping, and even hotels. Autogrill is one of the chain restaurant/cafeteria/supermarkets that has the concession by the company that operates the freeways in Italy and it has great food.
I would also suggest that you don't take the A7 to Genoa, rather from Malpensa take the A4 toward Novara/Torino, then past Novara, switch to the A26 toward Alessandria then to Genoa via the E25. That route is faster and with less traffic than the one through the Tangenziale (beltway) around Milan to the A7. Check a map (online if you want) to see the route I described.