For big numerical stuff and things that need to run on supercomputers, C/C++/FORTRAN are definitely very relevant and I don't see that changing. Likewise for edge stuff that has to run on bare metal or embedded, I think we're still going to be using C/C++ for a long time to come.
"Scientific computing" is a huge range of different use cases with very different levels of numerical intensity and amounts of data. I doubt very much that there would ever be a one-size-fits-all approach.
However in the context of the OP, I'm arguing that Go would be preferable to Python for the purpose of writing bioinformatics models, and certainly more suitable than Lua or JavaScript.
Of course Python can sometimes be very performant if you leverage NumPy/SciPy, since those are ultimately bindings into the FORTRAN numeric computing libraries of yore. But if we're talking about writing the inner loop, and the choices are Go, Python, Lua, and JavaScript, I think Go is going to win that on the performance and interoperability fronts handily (I omit Crystal, as I am not familiar with it).