I like the idea of a 9 ton 5/8 boat. It'd make a nice light harbor patrol boat, and dice knows the full spread of the Star League probably had a lot of harbors...
That was my thought as well, along with the 12 or 15 ton hydrofoil for interception work. In fact, I can easily see a pair of boats being designed to share the same small engine with the little harbor patrol boat making up the bulk of the fleet for day-to-day work and a handful of bigger, faster, and better armed hydrofoils in case of emergencies. You could also use the 90 and 99 ton hydrofoils as fast ferries, although I feel like it would make more sense to use a fuel cell than an independent fusion plant for this because they are probably not going to need the independent operations or energy weapons of the patrol boats.
The other real uses I see are the 5 and 11 ton VTOLs which would be useful for military recon work or, more likely, civilian vehicles intended for extended operations in remote areas or long endurance flight.
Now I see a tactical use of SMs cruising for 12 hexes, making six turns in a tight donut around the target. Do something like the Indian riders circling an impromptu wagon-fort and keeping them penned in. Just do that with a half-dozen SMs...
...and pray they miss a kick...
That is only covering 6 hexes a turn so you will be easy prey for their weapons. A better strategy is to only plan on pinning something for one turn so you can dart into position with good defensive mods and then bail out the next turn. When used strategically this can pin an enemy in a very bad place and potentially set you up for a kill without sacrificing your hovers (or at least not many of them).