Vaut is the third person singular of the verb valoir (to be worth, to have a value).
The order of the words in that sentence is not the usual one but is typical for a proverb/aphorism.
The words can rearranged to better match modern usage in:
Tard vaut mieux que jamais. Literally: "Late is more valuable (lit. is better worth) than never".
which is ...
Mettre en attente is unambiguous in the context of a phone call, that means the audio link between you and your party is suspended. Otherwise, that would be something like je vais vous demander de patienter, ne quittez pas and similar sentences already listed in the other question which do not necessarily mean you'll be put on hold.
Le bouton hold is not an ...