Overall leader Greg Van Avermaet of BMC held on to the yellow jersey for a sixth day but after a mass fall held up around half the peloton 17km from the line Ireland's Dan Martin trailed home 1min 16sec off the victor bleeding at the elbow and with his Tour hopes severely dented.
Van Avermaet is unlikely to keep the jersey for long once the race hits the mountains.
"I was following good wheels but it was choppy".
"I was on the ground before I knew it and straight away felt pain in my right shoulder", said Porte, who was diagnosed with a fractured right clavicle. "It's a insane moving circus around France and every day is different".
"Even before the doctor had looked at me and told me it was broken and I was going to be going home".
German John Degenkolb of team Trek-Segafredo became the victor of the very dramatic ninth stage of Cycling's Tour de France in 2018.
Neither of their falls were as serious as that of Porte, whose race was ended by a stage nine crash for the second successive year. That increased his lead over Froome's teammate Geraint Thomas to 7 seconds and his own BMC teammate Tejay Van Garderen to 9 seconds.
My back's against the wall, says Cavendish
"It's really hard to describe", Degenkolb said after crossing the line.
The Colombian has been in great form so far and was looking for his third stage win of the race.
Mikel Landa also lost seven seconds, having crashed while trying to take a drink from his bottle before being paced back by his Movistar squad as their other leaders, Nairo Quintana and Alejandro Valverde, finished safely in the main bunch.
After catching Sagan, Quick-Step Floors' Fernando Gaviria and Lotto-Soudal's Andre Greipel clashed and were both relegated, but though the German reacted angrily on Twitter his punishment was for a seperate incident involving Team Sunweb's Nikias Arndt. Thomas lies second on the general classification, 43 seconds behind Van Avermaet.
It was an impressive performance from Bardet to limit his losses, given the AG2R La Mondiale rider suffered three punctures during the stage.
The pelaton will enjoy their first rest day on Monday before Tuesday's 10th stage from Annecy to Le Grand-Bornand.
"I've had bad luck, but I always had the will to come back to my best".
A chance of Sunday showers and storms
Thursday and Friday should remain sunny, although there's another chance for showers and thunderstorms this weekend. In addition, there may be some vivid lightning and damaging, straight-line wind gusts within any of these storms.