Yes I could combine them, However, you might get two items in a small flat rate. The medium flat rate is 10.95. It would probably be cheaper to mail them separately in manilla envelopes First Class (around $2 each).
I shipped a dress to Texas in a manilla envelope First Class and it cost $1.92. So I would guess around $2, however with listia it has to be exact so I'd have to have a zip code :)
A small flate rate box costs $5.20 and it's really small (8-5/8" x 5-3/8" x 1-5/8"). You'd be lucky to get 2 size 9 items in it and at that point it would be cheaper just to ship it first class mail in a mailing bag, anyway.