The Adios 9 is the old idea of a racing shoe, kept alive: a thin slab of LightstrikePro, a small stiffening element in the midsole to keep the toe-off snappy, and not much else. It sits under 30 mm at the heel on a 7 mm drop, which by the standards of a super-shoe is barely a shoe at all.
It suits you over 5K and 10K, and in track or tempo sessions where you want to feel the ground and turn your feet over quickly rather than be carried.
It is not cushioned and it is not forgiving. Much past an hour it will start to beat you up, and if you have come from a tall soft trainer the first run in these feels unusually harsh. Treat it as the sharp shoe in a rotation, never the only one.