Floor Support Repair

Slight sway in kitchen floor. Removed divider wall in basement and discovered previous homeowner had moved a stair entryway; dropped in 2x12 joist pieces that aren’t supported outside of hangers. Resulting in a distinct dip and sway along the effected area. I have a 9 ft span that needs support in order to level. Looking for advise on support beam size and if I can support the beam with two steel basement style columns.