Instead of editing your original post, it is less confusing for readers if you add a new post answering the questions.
Since you have a 9 twist, you should consider a heavier bullet. The 9 twist is ideal for 65 thru 75 grain bullets. Some weapons will stabilize the 55 and produce OK groups. However, when loaded to it’s potential with the heavier bullet, you will get noticeably better groups, especially at/beyond 200 yards, especially in a wind.
My choice would be the Sierra 69 HPBT.