I think we have some misunderstanding here.
It seems that your idea of “up” and “down” a hierarchy is opposite from the way I interpret it.
With “uC” I usually think of a micro-controller, which does not have buses, but just I/O pins because all peripherals are integrated on the chip. (But they often do have I2C, SPI and other serial buses). You probably mean a microprocessor system such as the Z80 68000 etc, which have address and data buses.
Address and data buses with numbered signals work in KiCad. Control buses with named signals are not fully implemented.
Maybe Rene’s tutorial on hierarchical sheets is useful to you:
I am not good with generalisations, I need more concrete examples to give better answers.