Can't say much about the late seating for dinner. If you want to make sure you get early seating for dinner, then you have to book early.
However, I never noticed before that Disney considers the rooms with two little port holes to be the same catagory as the other Large Porthole Rooms. Disney needs to either recatagorize these as Cat 10 (like the secret port hole rooms) or redo the catagories to add another catagory for these rooms.
Unless it was made obvious to your parents that booking a GTY Category 9 put them as risk of getting a small port hole room, then I would raise a ruckus with
DCL to demand that they either give you a discount (something equivilent to a Cat 10 room, or at least split the difference between Cat 10 and Cat 9) or get reassigned to a large port hole room or so other upgrade.
It's only if you go looking into the details that you discover there are Cat 9 rooms with these small port holes. DCL's marketing material (such as the free marketing DVD you can get with about 2 hours worth of information) seems to pretend those rooms don't exist.
On a side note, that was something I was very disappointed in with the DVD. The didn't really show you all the different room types. As an example, they show you the same cabin for Cat 5 and Cat 4 (the difference being the Cat 4 is bigger because of the murphy bed).
But to reiterate...
It's your own fault for not booking early enough to get early seating (i.e. DCL hasn't done anything their).
But as for the room, based on what I've seen with their marketing, I'd complain until I got satisfaction as there is no equitable comparison between to two small port holes on Deck 1 and a huge port hole that you can sit in on Deck 2.
Basicly, you've got several valid and fair arguments with DCL over this cabin assignment:
1) You were (probably) not made aware of the fact that booking GTY 9 means you might get assigned with two little port hole (like I said, the marketing material always shows the large port holes).
2) Not only are the port holes smaller, but they are also on a lower deck from the "better" port hole rooms listed in the same catagory (generally, higher in the ship is higher catagory, for example, Cat 5 and Cat 6 are the same except Cat 5 is a higher deck, Cat 12 and Cat 11 are the same, except Cat 12 is Deck 2 while Cat 11 is Deck 5 thru 7).
Good Luck!