This is a really impressive Monday. There are six theme answers, two strong long downs, and not much to complain about in the fill.
The theme itself is fine. The weakest is IRONWOOD. I mean, I know it's a recognized name for a number of hard woods. It just left me a little cold. Maybe I wanted Ironweed, a reference to my neck of the woods, written by William Kennedy. Never read it, never saw the movie. So what am I actually complaining about? I'm not sure.
I liked FIREBIRD, especially since I read the clue ("Larry, shoot!) and put in FInEBIRD. As in Larry Fine. It's the bias of recent exposure (see Fridays puzzle). I somehow justified it with "shoot" referring to giving the finger? Thus, bird, see? Like flipping it? Anyway, OnEOS was very confusing. Until I recognized I'd missed the pattern. And Larry Bird is much more exciting than Larry Fine. Interesting Boston slant with BRUIN.
But of course the best is GRINDSTONE.
BOGGEDDOWN is great, with those pairs of doubled letters. SUBTLETIES is also excellent. I also like CATTY, WOBBLY, and LATKE.
1A: "Away with you!" (SCAT). Huh. It's okay. I wanted "Shoo" but got "Scat". I am looking forward to the first 1A answer I actually enjoy. I'm giving this a C+.
Otherwise a good Monday, for sure.