Sorry, they are likely to be crabs. Everything evolves into crabs.
But convergent evolution is a thing. And if becoming a technological space faring civilization is difficult (or equivalently, slow/unlikely), then it is somewhat reasonable that the fastest way of getting there might be somewhat similar.
We have reason to believe that interstellar civilization is hard, and (if we pull it off) we'll be among the first in the universe to do it. More accurately, it seems plausible there are zero in our past light cone, because once you can pull off interstellar civilization it should expand at a non-trivial fraction of the speed of light.
So, given that, maybe somehow our humanoid shape is a short and "easy" path to interstellar civilization, and ditto our social systems.
An intelligent life form without enough competition and arrogance might dwadle away at perfecting life for a billion years before bothering to cross the gulf between stars. One with too much violence and not enough cooperation would self destruct when before it could handle the energy scales of interstellar travel.
Similarly, while lots of species on Earth have gotten quite smart, humans are
Dry land livers, which may be needed for the early stages of the technological singularity
Possibly bilateral symmetry works better on dry land than alternatives do. So while non-bilateral symmetry can evolve technological intelligence, that might add many billions of years to the expected budget.
While climbing trees might seem strange, the existence of trees on a Earth is what gave is Coal, which was a huge part of bootstrapping technological civilization. Trees are trees because they evolved a super-strong material that lets them grow tall and crowd out competition; that super-strong material doesn't decay easily, leaving to huge deposits of dead trees that form into coal. Climbing trees gives you a pre-intelligence reason to evolve grasping hands with opposable thumbs, which in turn make even early artifact-based technology (shaping rocks etc) plausible, which in turn places evolutionary pressure on more abstract intelligence.
So plausibly we have bilateral, land based, climbing species with hand-like graspers having a huge advantage over other species at forming technological civilizations, and a narrow band of competition and cooperation needs to exist in their society to both make them do the stupid thing and go to the stars, but not so stupid as to destroy themselves with their technology.
Our forward facing binocular vision is a hunting adaptation; hunting was one of the first yields of intelligence, as it took a tiny primate and let it consume the planet's megafauna as calories, spreading it over the entire planet. Hunting led to herding and biotech breeding of both prey species and photosynthesis crops -- both of them where key in pulling us into the stone age of technology.
Alternative paths to interstellar civilizations are possible. All it requires is that this be a short cut compared to others. Like, biofilm intelligences living in a holographic computational model on an ice planet might develop physics and tool use and the like eventually, but maybe it takes an average of 30 billion years for that line to play out. And maybe liquid methane based life is viable, but their slower metabolism means that the evolution speed is also slower, so they are billions of years slower again.
Meanwhile, our pattern of interstellar technological civilization takes an average of 10 billion years, and the outlier fast ones take a handful of billion (like we did) to rise up from non-life.
So in this hard SF situation, humanity has colonized a few dozen galaxies when it starts seeing evidence of another civilization a few giga light years away. We continue to expand, and knowledge of that civilization crosses human space. A few more doublings of human space later, the two civilizations finally get into contact, call it 2-50 billion years from now.
Everyone is shocked at the fact that the origins of these two civilizations, as far removed from the current beings in them as we are from non-celled abiogenesis in a tidal pool somewhere, looked similar. Funny that.
Oh, and we know we are fast for the simple reason we have a fallow planet, and not the interstellar equivalent of a parking lot.
Look at what humans did to Earth -- almost the entire planet is turned into a giant tool to advance human wants. The biomass of land mammals has massively increased, fed by our converting huge amounts of plant mass into food for us and our livestock, while wild mammal biomass has plummeted. (Non-mammals, like ants, are at the wrong scale, so care less about what we do at our scale)
A successful "hard SF" interstellar civilization based off of humans is likely to do the same to the entire solar system, then galaxy, then multiple galaxies in a wave of expansion that moves at a non-trivial fraction of c (say, 0.001 c?) after it passes its initial stages.
They'll arrive in solar system with "pond scum" as the highest form of life and disassemble planets, build custom biospheres, etc. They won't be intentionally destroying the possibility of the system evolving independent intelligent life, but it will be a byproduct.
When they find "higher" life, they'll still meddle over evolutionary time scales, because entire solar systems are places that could support millions of billions of intelligent beings for billions of years before any intelligent life would naturally develop and reach to the stars; a lot of potential to sacrifice for the equivalent of a trilobite. Unless that life is extremely rare (which this hypothesis doesn't require), at best a few reserves may develop. But those reserves need to last for astronomical periods of time for life to evolve technology independently there, which is also ethically fraught. Why not give that life a leg up?
In this "hard" SF universe, millions of different biologies can be possible, billions of different intelligent patterns could exist; but whichever one is faster at reaching interstellar civilization swallows the local universe. And as we haven't been swallowed, it must happen that our pattern has to be pretty fast.
Naturally in the billions of years it takes to spread our interstellar civilization, we'll continue to evolve.
So, by the time we reach the other species, billions of years in the future, the two crab like beings will marvel at how their form when they left their home planet looked similar. But neither side will be surprised the other looks like a crab, because it will be well known that everything evolves into crabs.
Via https://xkcd.com/2314/ :