Rental cars are available at the Malaga airport from both large, national companies.   Small, local agencies rent cars as well.   One to try is Caramba Car  which has a variety of cars and 4x4s.  Roadways can be crowded so caution is advised if driving.  
 
For scooter rentals try Moto Mercado , Plaza de las Comunidades Autónomas, 95-205-26-71.   You need a valid drivers license and must be at least 16 to rent a scooter or cycle.  

Taxis are plentiful at the airport and affordable.  Torremolinos is only a 15-minute taxi ride from the airport.  Most taxis have a set rate for commuting into the city so ask up front about the costs.  It should cost about 13-15 euros.  For taxi service within the city call Radio Taxi at 952 372 915.