Can a WDL10 be used to switch a higher load than the units is rated for ?

Yes 
Use the day light switch WDL10 to operate a contactor or 600RM

Please note the large LEd flood lamps have evry large inrush current and can weld contacts
Schneider electric some High preformace contactors switch switch the load at Zero crossing of the wave form to help with arcing of contacts
 
A9C15030 contactor modular https://www.schneider-electric.com/en/product/A9C15030/ict-plus-20a-1p-uc-230vac/
A9C15031 contactor modular https://www.schneider-electric.com/en/product/A9C15031/ict-plus-hc-20a-1p-uc-230vac/
A9C15032 impulse relay   https://www.schneider-electric.co.in/en/product/A9C15032/impulse-relay-itl%2B---1p%2Bn---1no---16a---coil-230-vac-50hz