Davao is excellent for macro life. The best sites are located along Talikud Island from Dizon Wall to Babu Santa Beach and beyond.
Babu Santa beach is the best macro site we have ever dived. It's white sand with all the rare stuff in spades. Very good for many species of snake eel, shrimps, frogfish (several species including warty clown, giant, painted, band tail), pipefish (robust, winged, halequin, etc), scorpionfishes (inc leaf and waspfish), many species of lionfishes, seahorse (common, thorny and pygmy bargubanti), etc, etc. Also seen blue ringed octopus, wunderpus, flaboyant cuttlefish - everything. Rated by a close friend and macro diver as second best in PI's after Anilao.
There are also many sites along Samal that are good, but do not measure up to Talicud - mainly because sharp eyed divers know exactly where to find stuff.
On accommodation/diving, call Frank Rasmussen, Davao Scuba.
Davao Scuba Dive Center
He can arrange diving and accommodation from Blue Jazz resort on Samal. Blue Jazz in new and has good quality accomodation + pool + nice bar and restaurant. It's owned by a pilot from Ireland and he has quickly developed an excellent reputation. IMO, it's the best place to stay.
You will need a good macro guide. Maeng who works for Davao Scuba is probably one of the best macro guides in SE Asia. He is a marine biologist and knows what to look for and where to find it. He is very familiar with all the good macro sites and is a great guy and a pleasure to dive with.
Suggest that you call Frank to discuss what you are particularly interested in shooting before you arrive/your requirements. He has a very good purpose built dive banca and will arrange rinse tanks. etc and, importantly, give you good freedom to dive in your own style.
Enjoy Davao!