The fun pool party involved a colorful cake, cupcakes and balloons, with El Moussa sharing a family snap on Instagram to mark the little girl’s actual birthday on Sunday.
“Today is the big day!!!!!!!! It’s my Baby Girls Birthday!!!!???!!” he excitedly captioned the photo. “Boy does time fly!! I can’t believe Tay is 9 years old!! I remember when we filmed the home video and Tay was in Christina’s belly!”
“I’ll tell you what...there is NO WAY I would have survived the last few years if it wasn’t for my little girl❤️,” he continued. “We are so close and she’s my best friend in the world! Before I was a parent, I never realized how much I could love a child.”
The proud papa continued to gush, sharing how his darling girl has kept him “grounded” and motivated.
“I’m seriously the luckiest dad alive!!” he said. “This little girl is my Rock! She keeps me grounded and motivates me to be better every day. Happy birthday from the world Tay we all love and adore you!!❤️❤️❤️.”
El Moussa also shared a pic after the party on Saturday, showing him and Young posing with Taylor.
“We had the best time at Taylor’s 9th birthday party at her moms today!!” he wrote. “While the kids were swimming I was in the corner shoving cheeseburgers down my mouth. ... even after I promised myself I wouldn’t lol...#whatdiet”
“Seriously @heatherraeyoung and I had a great time!” he continued. “It was the first time we were all together and it was great❤️. Tay and all her friends got to make slime, play games in the back and swim! She had the best day and she SCORED at her soccer game again!”
Young shared the same snap while opening up about how she has become close with Taylor in recent months.
“Tay and I have really bonded the last few months,” she wrote. “She welcomed me with open arms & since then we have enjoyed our girly days, shopping getting our nails done & getting matching friendship necklaces. Happy happy birthday Tay!! ❤️.”
While making his red carpet debut with Young earlier this month, El Moussa opened up to ET about how well introductions had gone between Young and his children. He added that she and Anstead were also getting along great.
"It all worked out great. I kind of threw that at them last minute," El Moussa revealed. "I didn't tell her much. I was like, 'Hey, you're going to meet my friend' and 'Hey, you're going to meet my ex-wife.' I threw them together in the same room, next thing I knew they were talking about vegan food and running, so it worked out great."