Crescendo or crescente?
Crescendo when translated to english means growing. Crescente means growing.
Usually Crescendo is only used to mean growing in volume while crescente is used to mean growing physically.
So for example if you wanted to translate this english sentence:
Marco has been growing.
into Italian you would likely say:
Marco e in crescita.
or less likely:
Marco andato crescendo.
Whereas if you wanted to translate this:
Marca grew to 4.5 feet tall.
you would likely say:
Marca crebbe fino a altezza di 4,5 piedi.
However like I said crescendo is usually used only in terms of volume(and I don't mean physical volume but rather auditory volume)
But if crescendo can be used to mean growing in any context than why isn't crescendo usually used to mean physically growing?
Crescendo (gerundio of crescere) is the process of growing, it's like: growing up you'll find out, growing up you'll learn.
Crescente is an adjective describing something who's growing, for example: Un importo sempre crescente, an ever growing sum (like... Italian taxes).
About your examples:
- Marco has been growing: Marco sta crescendo. "Marco andato crescendo." Never (well maybe not never... but it sounds indeed odd). You can use "andare crescendo" with things, like the team's chemistry è andata crescendo, the politician's credibility è andata crescendo, Merkel's power è andato crescendo. Note that it describes a process.
- Marco grew to 4.5 feet. Marco crebbe fino a 4,5 piedi, Marco è arrivato a 4,5 piedi, Marco è cresciuto: ora è alto 4,5 piedi.