Time as text with O' or OH option

I’m strictly using facer, to create the time in text display, how do I add an O or OH, with single numbers, for example seven o’ nine?

any help would be greatly appreciated.

This formula only addresses the minutes -

$#Dm#<10?OH#Dm#:#Dm#$

The part before the ? is the comparison, then between the ? and : is the true statement, and after the : is the false statement.

If you want to get fancy with your double zeros, you can use:
$#Dm#==0?OhOh:$#Dm#<10?OH#Dm#:#Dm#$