The reason I don’t have an ounce of buddie doubt right now is because I do not think this show is gonna queerbait us.
We’ve been introduced to queer characters (queer main characters no less) since episode one. This show is very much intending queer people to watch it. They wouldn’t have to make new potential queer characters because they’ll still have a substantial queer audience.
The creators and actors are both super aware of buddie and fans’ thoughts about them. If they don’t want buddie’s relationship to be romantic, they could’ve toned down on the romantic chemistry between Buck and Eddie a long time ago. Yet they keep pushing it. They didn’t have to make Buck canonically bi. But they did. 
Still, they could’ve given him and Tommy a healthy and beautiful relationship that is slowly built up over time, like the other main couples in the show have if they really wanted them to be end game. Yet they continue to give them unhealthy conflict throughout season eight. Much of which is about Eddie. It’s normal for couples to fight, and even temporarily break up, but the reason Buck and Tommy not getting back together being about Eddie?? That has to mean something.
Meanwhile, Buck and Eddie’s relationship has been building up for seasons now. We see them hanging out outside of work, they communicate, they express their care for each other in more ways than one. Eddie (along with Christopher) is shown to be of utmost importance to Buck. They take care of each other when they’re hurt, they care more about the other’s opinion than anyone else’s, and they always make up when they argue. Compare that with the three genuine scenes we get between Buck and Tommy (and even that’s pushing it), and buddie has way more chemistry than they ever will.
Also the fact that not one but two people suggested, straight to Buck’s face, that he might be in love with Eddie?? In the most recent season (when by now everyone knows about buddie’s existence in the fandom)?? I don’t think that was an accident.