The SKIMS founder shares North with her ex, Kanye West.
Kim shared several photos to mark her oldest child's birthday, including mother-daughter snaps, throwback pics and glamorous shots.
"Happy Birthday my baby, my bestie, my everything," Kim captioned her post. "There’s no one like you! The most honest, creative, silly girl with the best heart. I just love being your mom, So THANK YOU for being on this journey with me. I love you til ♾."
In addition to North, Kim and Kanye share Saint, 6, Chicago, 4, and Psalm, 3.
Kris Jenner, North's grandmother, also chimed in with birthday wishes, sharing photos of North with her mom, siblings, and other family members.
"Happy 9th birthday to my beautiful granddaughter North!!!! I can’t believe how fast you are growing up!" Kris wrote. "You are such an amazing young lady, an amazing daughter, granddaughter, sister, cousin, friend and the most fabulous stylist extraordinaire!"
"You are so kind, smart, creative, clever, funny and quite the athlete!!" the proud grandmother continued. "You are beautiful inside and out and I am so very proud of you my little Northie and I love you more than words can describe!!!! 💕💕💕Lovey"
The birthday love came after North and Kim gave fans a peek at the eldest West child's upcoming birthday party on their joint TikTok account. In the video, the duo revealed that North has opted for a Kuromi-themed bash this year, complete with a life-size version of the character and lots of merch.