It is not necessary to walk from CSR.
Buses run between Epcot & BB until 11 p.m. You just need to take the bus from AKL to Epcot & transfer there to the BB bus.
The bus from Epcot does stop at all 4 stops at CSR before going to BB, so it takes longer. Total travel time AKL to BB via Epcot should be 40-70 minutes, depending on how long you wait for each bus.
If you take the bus back after golfing, remember that the last bus leaves BB at 11 p.m., so finish up by 10:50 or so. After Epcot is closed, the driver will usually take you direct to your resort from BB.