my plants have that "sunken" look too when i stop watering in the winter months ..... but as soon as the plants are returned to weekly watering - those "sunken" areas swell-up and almost go away ....
your plant is ready to be planted whenever you want ....
roots look okay ....if roots feel a little soft, it may be because of a lack a water ...
if you want a "bonsai look" - plant 1 inch higher in the pot ....
water thoroughly once every 5 days - or every 3 days if temperatures are above 100 F ....count rainfall as a watering ...if it rains, wait 5 days to water again ...
make sure as you water, that water is freely running away from the bottom of pot ....and never let adenium sit in water -