The owner of a nearly $9 million Malibu mansion miraculously spared being leveled by the raging Los Angeles wildfires told The Post on Friday he was stunned to learn that when the smoke cleared, it was still standing.“It’s a miracle — miracles never cease,” said retired waste-management exec and married dad of three David Steiner, 64, of Texas.Steiner said he thought his stunning three-story California structure — which was vacant at the time — was a goner when a local contractor sent him video of flames and smoke engulfing his property and his neighbors’ Tuesday.“[The contractor] was watching the news reports and saw my neighbor’s house going down and told me, ‘It looks like your house is going, too,’’’ Steiner recalled.The ex-exec said that when he got the video, “It looked like nothing could have possibly survived that, and I thought we had lost the house.’’Then people started contacting him saying, “Your house is all over the news,’’ Steiner said of the extraordinary photos capturing his unique white three-story structure standing like a beacon in the middle of the charred smoking remains of neighboring multimillion-dollar properties.“I started getting pictures and realized we had made it through,’’ Steiner said.“My wife sent me something this morning that said, ‘Last house standing.'” And it brought a pretty big smile to my face at a pretty bad time.”Steiner, a lawyer and former head of Waste Management, Inc., in Houston, said he believes that his property’s ultra-sturdy construction — likely designed to protect it from earthquakes — saved it from the Palisades Fire that destroyed the homes all around it.“It’s stucco and stone with a fireproof roof,’’ he said, adding that it also includes pilings “like 50 feet into the bedrock’’ to keep it steady when powerful waves crash into the seawall below it.“To be totally honest with you, I never in a million years thought a wildfire would jump to ...