There are learning disabilities issues that are borderline... Asbergers (sp?) being the most relevant. However, the results were not definitive enough for a positive diagnosis. This may be in part due to us pursuing a course of counseling early that has shown some progress.
Then you need to understand what the tests meant. Just because the state declares the condition one that they don't need treatment for its still an issue.
Let me try an example. The state may declare that someone is legally blind when eyesight is 20/200 and therefore someone with better eyesight is "borderline". This doesn't mean the condition isn't a problem, only it is a problem the state has decided to ignore.
If it were my children I would pursue too fronts in addition to your homeschooling. First, I would get copies of the tests and consult with specialists in the field that were called "borderline" and get their assistance for a lesson plan and accommodations. Second, I would obtain an advocate versed in the law that requires public schools to insure an adequate education. I believe that the school may be required to lend assistance.
The Saxon website does have a section where the kids can take an online test to determine the level at which they would perform best. Our son attended Catholic schools til grade 5, but never really got a good grounding in the basics. We began homeschooling him in the 6th grade, using Saxon for two years, and Jacob's Algebra for a year. He returned to school in the 9th grade, and took Algebra again in that grade, then Geometry in the 10th. Hubby started working with him in Alg. II, but we decided to try the Community College. He tested into College Algebra at the college, and will take that course in July.
If you are unsure of yourselves in this, going with a boxed curriculum with oversight from an organization is a good idea.
A lot of lights went on for me when I discovered "Asperger's syndrome." School can be hell for the brilliant, inept kid, the one who will not, indeed can not, "fit in." Bullies serve the same purpose in schools as rapists do in prisons -- enforcing the norms, punishing the misfits, inculcating a sense of impotent rage. As a mid-50s grownup, I can make light of the syndrome -- "The world is really an interesting place when you see it through my eyes!"