I'm not a mother (but I am an aunt to 6 kids) so I guess take my ideas with a grain of salt. I'd go with some sort of adult lighting which complements the space (perhaps one hanging fixture, or a row of them on the beam?) And, add in some table lamps to make it cozy. I would think the main goal would be to make it nice and cozy for a small child. My view is that the decor should be functional and should not have to be changed out as the child grows. You can bring in the "fun" stuff with linens and other accessories, rather than getting a bunch of stuff a fickle child might not even like down the line (or appreciate at age 2 1/2) and which you'll just end up getting rid of. Then again, I have never really understood decorating children's rooms or nurseries in strongly "child-like" or baby colors and themes. ;-)

Cubes where the room is not wider or longer in at least one direction than the ceiling is high are not particularly comfortable, similar to how large rooms with low ceilings are not particularly comfortable. In a cube, the room tends to start feeling shaft like, where a large room with a low ceiling often seems to sag or press down in the center. Also, cubes are static and rectangles are not. It might be better if the ceiling was 15-16 if 24 is the largest dimension of the room. Peaks are a little different. I lived in an apartment where the original parlor floors were essentially a golden rectangle. They had been lofted at one end (about 1/3 of the space) and it made the high ceiling in the remaining area kind of elevator shaft-like. The apartments that maintained the original proportions were more comfortable spaces. Of the above pictures Mutiny and Rufty seem fine because of the length of the room and the ability to experience the height from the opposite end of the room in some sort of perspective. I actually find the Shades Creek kitchen proportions unpleasant. It makes a good picture but I don't think I would like working in that kitchen. I am curious as to how many people with 8-9 foot ceilings vacuum or clean them on a regular basis. I am not sure the extra height makes rooms extra dirty? That said I had to clean my 14 foot LR with elaborate plaster cornices with an extention pole with brushes on it...I purposely did not have any lighting in that ceiling. I think the people who bought the apartment from my buyer put in recessed cans. (Not right in a 1830s house and very hard to change. A ten foot ladder is much harder to manage than an 8 foot ladder).

if the high point of the ceiling isnt symmetric with the sink... i'd skip highlighting that. have your splash match the bottom of your uppers OR some sensible spot on your hood higher than the bottom of your uppers if its like... 20". dont go higher so you can ignore the vault. if you intend to tile to the ceiling of your hood wall... stay at 18" on your sink wall with or without uppers.

The contractor is looking for the quickest, cheapest way to make this problem go away temporarily. Maybe he's hoping the next time you call him he'll be retired and can ignore you. It's not normal to have to fix this periodically. In addition to the annoyance factor, you don't know what this is doing to cause hidden damage to the structure, which could be very costly to fix in the long run. Whatever it takes, get it fixed properly.