Well you see, we have a feature called "Ranked Battle" & "Great Ninja War" and even "Team Instance" or "Strong Approaching" where you can fight multiple teams at once where the maximum number of units can go up to 27.

Amazing right? What a time to be alive.

When they say hits 12, 7, 9 etc. they generally mean that it will hit other teams, going to the effort of explaining that it hits 9 and it being limited to one team would be silly because it's simpler to say "Hits the entire team", as in the particular team you're targeting.

But it's true some cases such as Tendo & Gaara they say "Hits the entire team" but they attack the entire enemy field instead. But localization issues aside, when they list a specific number of targets, they really mean that they'll find that number of targets even across multiple teams.