Problem solved! Eto ang ginawa ko to isolate the problem:
1) Connected the BD directly to the PJ using the 35 ft cable ---> 3D worked which means my long cable is 3D capable talaga.
2) removed the onkyo 809 from the rack and placed it near the PJ. Connected the PJ and the BD to the Onkyo using 2 of my hdmi cables that were proven to work with 3D ---> no 3D! So mukhang onkyo ang may problem.
3) tried to fidget with the onkyo settings (turned off deep color, disabled all video processing sa onkyo) ---> still no 3D. At that point, nawawalan na ako ng options.
4) Finally, I decided to reset my onkyo to its factory setting ---> 3D worked!
Di ko alam ano ang nangyari. Anyway, happy na ako that everything is working fine. Will re-calibrate na lang later.
By the way, I decided to repaint my DIY screen yesterday, this time using light gray paint (white flat wall enamel + small amount of black tinting color) then put a 4 cm felt paper (black) border all around. Mas maganda siya compared sa white. Black levels improved, yung whites naman eh di naman naapektuhan gaano. Better ang felt paper compared dun sa previous na black painted border kasi gloss black paint yung nagamit ko before at may reflection kapag natatamaan ng ilaw