My guess is that you’ll be fine, but that the coach, who probably extended the offer recently, doesn’t want to “waste” your ED if it’s not a go from admissions. That’s a decent move on their part and an indication that there is some risk.
AOs tend to be understanding when there’s been an upward trajectory. They are getting the applicant at the end of that trajectory, not the beginning, and there are lots of reasons why some students falter at the beginning of high school. Recovery is more important than the rocky start.
For your part, you should take whatever you learned from that and use it to ensure you are successful in college. (Time management will be key as will keeping up with your work without daily assignments to submit.)