Oliver Stark Says Buck Fosters Theo in 911 Season 9 Finale

The 911 season 9 finale made Buck the foster parent of preschooler Theo after Theo’s parents died in a car crash. In "Hearts and Flowers," ABC’s 9-1-1 reset two main story lines at once: Buck stepped into a role he once avoided, and Athena ended the episode on track to become a detective.

Buck and Theo

Oliver Stark said Buck’s decision is "Like most decisions, it’s a little bit of both, right? Everything all at once," a mix of duty and obligation. Buck is Theo’s biological father, but he previously wanted as little to do with him as possible because he had been the sperm donor for his friends and did not intend to be part of the child’s life.

That shift gives season 10 a built-in family story with stakes that reach beyond Buck’s own history. Tim Minear called it "going to be a gold mine for story," and Stark pointed to "the opportunity to delve into why he maybe did have to step in here… Who else is in Theo’s life, and why hasn’t he been helped out further by the foster system?"

Athena and McCluskey

Athena’s arc closes on a different kind of turn. She survived one fatal injury in the police corruption case she has been working on, then survived one follow-up assassination attempt in the hospital, and by the end of the finale she is becoming a detective without the field sergeant title. For a character who had already been doing detective work for a few seasons, the promotion formalizes what the show had been treating as reality.

Minear said Buck’s ending left room for the harder part of the story, adding, "I think it’s completely within Buck’s character to make a decision like that without thinking it through entirely," and, "But he absolutely wants this right now." He also addressed the finale’s emotional tone, saying, "Maybe I played the ending wrong, because I seem so happy that Theo is there, and am I thinking about the tragedy that he has to be there because his parents died?"

Season 10 setup

Minear answered that concern directly: "I don’t think he played it wrong at all. I thought he played it perfectly, but that’s really the exploration for Season 10." Peter Krause did not return for the episode because he had moved on to his pilot at that point, and Minear said, "Obviously, if I could have done something like that, that would have been great," after explaining the absence.

The finale leaves 9-1-1 with two concrete changes, not a soft tease. Buck is now tied to Theo’s future, and Athena is moving into a detective role after surviving the case that nearly killed her. That makes Season 10 less about resetting status quo and more about whether Buck can carry a child he once kept at arm’s length, while Athena’s new title finally catches up with the work she has already been doing.