US players generally apply about the middle of their last year in high school. I worked with a top player who just needed to get his ACT scores high enough for eligibility and they would take him the summer before school started. Don't know if there may be more paperwork for international students. However, if you are good enough for the team and meet the academic requirements for the school and general academic requirements to play Division I, deadlines should not be that much of an issue. With a team sport like soccer/football and not having US high school results, it may be harder for them to tell how good you are from looking at stats. Not sure about signing up for formal trials, but the coaches should be interested if you play at the level they are looking for.