You say shots 7-9 didn't pattern, I disagree. I think they shot about a 2-inch group, which is "ok".

First question, is it the gun or is it you? I always like to take a rimfire or centerfire to the range with me that I am 100% certain is accurate so that if my groups are crap, I can shoot the gun of known accuracy and confirm that I'm not having issues that day. Some days this is all I needed to learn it was NOT the gun.

Next, 110gr BH209 is a relatively stiff load for a new gun. I would start with any gun at a lower charge, maybe 80gr, and work up. With EACH different bullet tested. Expensive yes, time consuming yes, guaranteed to avoid frustration and let you know what is going on, yes. Some bullet/sabot combos will top out at 85gr for max accuracy in a given gun, when others in the same gun will shoot fine at max charge. If you jump straight to a middle powder charge, it's hard to say what's going on.

Finally, I don't like how you describe the looseness of the sabot. IMHO sabots are more accurate the tighter they are. No, you don't want to pound them down with a hammer, but it should take a firm hand to get them down. I would recommend a tighter sabot, or a different bullet/sabot combination completely.

A 2-in group with the first bullet/sabot combination, especially when it was loose, is not bad. It's a starting point. Keep working with it, you'll get there.