Def Fed TSS #9. Recoil is very reasonable in an ultralight 20g. (I may be biased, since I switched from a 10g that I had used for 20 years prior).
Not sure if they still make the 'reduced recoil' loads which were 1000 fps any longer. They were available the first year of production. When I resupplied last season after turkey season ended, I could only find the 1100 fps loads in #9. I still have 10 of the 1000 fps shells, and am saving them for my 12 y/o daughter to use. My son and I will be using the 1100 fps version this spring.
And don't have any reservations about using the 1000 fps shells... between me and my kids, we took 13 toms in the 2018 and 2019 seasons. No misses and only one loss when my son centerpunched a strand of barbwire 4ft from the end of the barrel. Most kills were in the 15 to 30yd range. One oops at 52 yards, but he dropped like a sack of potatoes.