The title contender crashed at high-speed on the Mont du Chat descent into Chambery after he misjudged a bend, and landed in the path of Dan Martin (Quick-Step Floors).
BMC sports director Fabio Baldato said Porte was conscious and asking for his helmet and sunglasses when the team car arrived minutes later. A race medic said he was "well-orientated".
The 32-year-old was taken away on a stretcher and transported to a local hospital, with team doctor Max Testa in tow. It was later revealed Porte had suffered a fractured clavicle and pelvis.
"Richie Porte was transferred to the Centre Hopitalier Metropole Savoie in Chambery where he was evaluated by Dr. Zerr. He underwent X-rays to determine the extent of his injuries. His condition was stable from the beginning, he was responsive and he remembered everything that happened before and after the crash," Dr. Testa said.
"X-rays confirmed a non-displaced right clavicle fracture and a non-displaced right acetabulum fracture. Richie also suffered extensive superficial abrasions involving the right side of his body. At this stage, the injuries will not require surgery. The plan is to re-evaluate Richie tomorrow morning and confirm that he is stable enough to be transferred home."
Testa said Porte will take several weeks of recovery before restarting his season.
"Normally, a fractured clavicle and pelvis would require four to six weeks recovery, providing there are no complications.
"If everything goes to plan, Richie could be back on the bike at the beginning of August and slowly build his fitness up from there. Based on Richie's recovery, we will re-evaluate his program for the rest of the season in consultation with BMC Racing Team management."
The Tasmanian entered the race as a favourite for the yellow jersey based on hot results this season. The 104th edition marked his first outright bid for the maillot jaune after he left Team Sky at the end of 2015 to ride for himself at the race.
His Tour squad was selected in December and had worked together since, all-in for July.
Teammate Greg Van Avermaet, who had done his bit and set-up earlier in the ninth stage, said he first heard about the crash from an AG2R La Mondiale rider on the road.
"At first I hoped that he was still in the race but now they have told me he is out," Van Avermaet said outside the BMC bus.
"It's bad luck for him because I think this year was maybe the year for him to have a chance in the Tour to win it.
"It's pretty hard for us because we came here with one goal and that was to put Richie on the podium in Paris," he added.
"We are all disappointed that he is not here anymore and he lost the Tour. But for us the most important thing is that he is healthy, he can recover from it and hopefully do some other races this year."
The news was a double blow for BMC road captain Nicolas Roche, whose cousin is Irishman Martin, who remains in the Tour.
"I think at the moment he [Porte] is probably not believing this happened," Roche said.
BMC had previously reconnoitered the climb, which has featured in the Tour before.
The rest of the team will fly from Chambery to Bergerac tonight ahead of tomorrow's first rest day.
Porte's former Team Sky boss David Brailsford went to the BMC bus after the ninth stage in what was a respectful move. The Tasmanian's family was not at the ninth stage that saw the Tour lose another big name.