This is a copy & paste of the law from this website: https://legislature.idaho.gov/statutesrules/idstat/title33/t33ch2/sect33-202/
TITLE 33
EDUCATION
CHAPTER 2
ATTENDANCE AT SCHOOLS
33-202. School attendance compulsory. The parent or guardian of any child resident in this state who has attained the age of seven (7) years at the time of the commencement of school in his district, but not the age of sixteen (16) years, shall cause the child to be instructed in subjects commonly and usually taught in the public schools of the state of Idaho. To accomplish this, a parent or guardian shall either cause the child to be privately instructed by, or at the direction of, his parent or guardian; or enrolled in a public school or public charter school, including an on-line or virtual charter school or private or parochial school during a period in each year equal to that in which the public schools are in session; there to conform to the attendance policies and regulations established by the board of trustees, or other governing body, operating the school attended.
History:
[33-202, added 1963, ch. 13, sec. 25, p. 27; am. 1992, ch. 243, sec. 1, p. 721; am. 2009, ch. 103, sec. 2, p. 318.]
I am not a lawyer but the way I'm interpreting this is if you are 7 on the day school starts, you must be enrolled in school. If he's turning 7 in a month, school has already 'commenced', so he'll need to start in the fall. I don't see this as a truancy issue.
Part of school evaluations often include a classroom observation. I think this will be needed before the school says a 1:1 is needed. Parent will not see this on an IEP or 504 until the child is in school & the school sees a need. Has the family considered a virtual charter school where they can provide 1:1 support? This might be a way to show the local school district that a 1:1 aide is needed.