How to deal with non UL DCDC converters?
we need to ship ASAP ...  What am I missing here?

Someone that understands the certification process.  If you had such a person, they would have been involved from the start, and not allowed you to leave certification as something to do at the end.  Thinking "We'll ship next week, just got to get this thing certified" shows extreme naivety to the point of incompetence.

Uncertified components

Ultimately, you want your whole product certified.  That can be quicker and easier if whole subsystems are already individually certified.  Your test house then can treat the subsystems as black boxes and not look inside.  If a subsystem is not separately certified, then they have to look inside.  This takes more time and therefore costs more, but does not by itself mean your whole unit can't be certified.

If you do go thru this process, it will cost less to get another product certified that uses whole subsystems from this one.  It is quite possible that the same testing house has already done this with your exact subsystems for another customer.  That will save them money, but they'll never tell you that.  From your point of view, if ADP won't provide a certification, then your test house will have to look inside that module enough to prove to themselves that it meets all relevant requirements for how you are using it.