The new deals for the pair ranked among the brightest young talents in the Scottish game mean that the club can look forward to long-standing quality and competition in the crucial position.
Kennedy, cousin of recently re-signed lock Grant Gilchrist, is a product of Alloa and Stirling County rugby clubs and represented Scotland at every age-grade before signing as an elite development player (EDP) in 2011.
He was included in Scotland's 2013 RBS 6 Nations training camp before excelling in his first senior representative match for Scotland A in the win over England Saxons at Kingston Park.
When captain Greig Laidlaw was ruled out of the opening few rounds of the current campaign, he grasped his chance to stake his claim for the jersey before a knee injury left the door ajar for Hidalgo-Clyne to get some exposure.
Kennedy said: "I'm really excited to be offered another extension, especially the way the team is going at the moment. We're definitely going in the right direction."
"On and of the field we've grown as a club. We're really tight as a group, it's like a big family and I think you can see that on the pitch."
"There's a lot of competition and quality at scrum-half, and across the whole squad, so hopefully that will continue to make us better."
Sam Hidalgo-Clyne joined the club's elite development roster in the summer of 2012 after a season as a Scotland 7s player.
He previously plied his trade with Forrester rugby club before being awarded a scholarship at Merchiston Castle School and representing Edinburgh and Scotland at every age-grade.
He then won a second scholarship, this time on the prestigious rugby experience in Canterbury, New Zealand, funded by the John Macphail memorial trust.
Sam returned to make his senior Edinburgh Rugby debut and now takes on captain Greig Laidlaw, fellow youngster Kennedy and summer-signing Grayson Hart for the number nine shirt as member of the senior squad.
He said: "It's fantastic to sign on again."
"I've been involved a lot more than I expected this season, which has been brilliant."
"It's now up to me to push on as much as I can and compete for the number nine jersey against some quality, experienced players."
Head coach Alan Solomons added: "It's tremendously pleasing to see young Scottish players come through."
"Sam [Hidalgo-Clyne] has progressed tremendously since the beginning of the season."
"He's had a bit of game time and I think he has a wonderful future ahead of him. It's fantastic that he's committed to Edinburgh Rugby."
"Similarly, Sean [Kennedy], who's a little bit older and more experienced, is also a fine young player and a tremendous prospect. Like Sam, I believe he has the qualities necessary to go on and play Test rugby for Scotland."
"Scrum-half is a key position. It's vital that we have good depth and we certainly have quality in that area with all available to play for Scotland."
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