This isn't that different from 2nd and 3rd grade math in the US. There's no algebra in your link, but either way, you're confusing algebraic concepts, which are typically introduced in grade school even in the US and Algebra 1, which is just a conveniently named part of the overall math curriculum, not one that introduces Algebraic concepts for the first time.
The page you linked to doesn't have a single problem that requires "setting up equations with unknown variables and solving them." And as I mentioned, even in the US, "Algebra 1" isn't when Algebra in the sense of equations and variables is first introduced. Algebraic concepts are explicitly introduced around 5th grade (https://www.khanacademy.org/math/cc-fifth-grade-math/imp-alg...), but problems that could easily be considered algebraic (whether through word problems or explicit placeholders) may be introduced as early as 2nd/3rd grade.
This isn't how that problem was meant to be solved - it's meant to be a straightforward subtraction problem. For instance, this is a US 2nd grade subtraction word problem from Khan Academy:
Sparky the dragon was born with 28 spikes. He grew several more spikes as he got older. Now Sparky has 80 spikes. How many new spikes did Sparky grow?
Sure, this could be expressed as an algebra problem, 28 + X = 80, but the intention here is quite clearly for the student to see it as a subtraction problem.
The point is that the types of problems you're referring to aren't considered algebra problems in math education, because students are expected to be able to solve them when they are introduced to subtraction, not when they are introduced to actual algebraic concepts. It's like saying when you learn to add integers, you're doing group theory because integers form a group under the operation addition. From a purely mathematical standpoint, sure, what you're doing could be explained using group theory, but from a pedagogical standpoint, it's nonsense, because you don't have to know anything about groups to be able to add integers or even to understand and utilize these specific properties of the set of integers.
It's entirely disingenuous, then, to refer to these word problems being solved by Russian students in 2nd grade, as though it has any relevance on whether it's appropriate to teach Algebra 1 in 9th grade. 2nd graders in the US are also expected to be able to solve these types of problems and it's not because they are taught any actual algebraic concepts.
