I am hesitant to endorse washing wool pants. What I would advocate is, once you get them clean again, to lightly brush them after wearing to help maintain their clean state. Does the wool need freshening or is it actually soiled? If it needs freshening, hang the pants for a few days in a bathroom which is also used for showering. With climate change I'm wearing more corduroy than wool. But my sense about wool is that it's easy to spot clean, whether you or a dry cleaner does it. It's not a fabric like polyester that magnetically attracts oily salad dressings from across the room. Spot cleaning and light brushing can preserve the overall cleanliness of wool pretty well. Well treated, in my opinion wool wears like iron.Lol! Well, I guess it wouldn’t be the end of the world if something tragic happened to them, but in the interest of adventure, I’d like it to turn out well, and I’m trying to do less dry cleaning overall to reduce chemicals etc. I’m wondering what would make unlined pants significantly different from a sweater? Do you suppose it’s just the weave? As you say, knit vs. woven?
Also, if interfacing is fused onto the pants to strengthen stress areas like pocket openings, that might pose a problem. If hand washing loosened or shrunk the interfacing I don't think you'd ever get it to look right. Bubbled fused interfacing can really ruin the look of a garment.
Supposedly, people who sew (c'est moi!) are supposed to test for shrinkage by taking a swatch of fabric, cutting out the exact same size in paper, clean and iron the swatch and see how it compares to the paper original. You would have to take a piece from a hem to get a swatch of any size and there goes the hem!
Can you call the manufacturer, get their opinion? If these were my pants, I'd get them dry cleaned maybe one last time and then maintain their cleanliness by spot cleaning and light brushing.
Also, garments that have some spandex (stretch) in them are IMO less liable to shrink when washed. But don't rub the wool, you don't want friction to start pilling. Just gently soak them in cool water, whatever Woolite says.