Yes. The D90 is now a dinosaur, but we have one of them beasts in our home camera arsenal. My partner uses it for happy-crappy snaps and it continues to function and to produce good, even fine images. All with the humble but impressive 18-55 it came with in 2010.
It was my first Nikon DSLR and I remain fond of it, even if nowadays I use my D700s and D800s, for some unfathomable reason I have two of each. These are likely to be my last ever digitals, which might explain the 'partner' camera for each. Also ten or eleven lenses or maybe even an even dozen, I long ago lost count.
The D90 went with me to Southeast Asia several times. It has produced, among many other fine images, two full page spreads published in architecture books in Europe, so it isn't a toy.
However, I agree your D200 is probably a better investment, but if the D90 is an almost giveaway to buy, well, why not...