What I am referring to are those that specify "commercial use allowed"

Again I am not a lawyer but if if it says commercial use allowed  then I see no reason why you can not sell reproductions oft he item.
Tin

so licences like CC BY and CC BY-SA means that if I make a candle wax copy of the 3d printed object that was printed from the file, I can sell it for a profit but I need to credit the author?

NO 

You need to read the licence. In general CC licences are for Non commercial use and you can not use the design to make and sell.
Some cc licence do allow  for commercial use
You need to read and follow the licence.
Most cc licences require you credit the author of the work regardless. .

What I am referring to are those that specify "commercial use allowed"

so licences like CC BY and CC BY-SA means that if I make a candle wax copy of the 3d printed object that was printed from the file, I can sell it for a profit but I need to credit the author?

NO 

You need to read the licence. In general CC licences are for Non commercial use and you can not use the design to make and sell.
Some cc licence do allow  for commercial use
You need to read and follow the licence.
Most cc licences require you credit the author of the work regardless. .

The comments I am about to give are my own and are not of any legal value , I am not a lawyer and not versed in intellectual property law or rights.

IMHO commercial use is commercial use.If you use someones design and profit  from it then it is commercial use  the medium and manufacturing methods are irrelevant. so a one word answer to your question  would be yes.

Not all cc licences are the same if you download a cc licences design read the licence and respect it follow the creators intent and wishes.

Some cc licences allow for commercial use.

tin

so licences like CC BY and CC BY-SA means that if I make a candle wax copy of the 3d printed object that was printed from the file, I can sell it for a profit but I need to credit the author?

what about BY-ND?

does it mean I cannot make wax structures out of it? that's the definition of derivative work?

IMHO commercial use is commercial use.If you use someones design and profit  from it then it is commercial use  the medium and manufacturing methods are irrelevant. so a one word answer to your question  would be yes.

Not all cc licences are the same if you download a cc licences design read the licence and respect it follow the creators intent and wishes.

Some cc licences allow for commercial use.

tin

what about BY-ND?

does it mean I cannot make wax structures out of it? that's the definition of derivative work?