The Grammar session can actually help with the Verbal section of the ACT and the Math subject areas can help with the Quantitative sections.

I'm pretty sure that Khan Academy has a contract with the College Board, and in the contract, Khan Academy is only allowed to have a formal SAT prep section. However, you may find the math, grammar, and science sections on Khan Academy to be useful in your ACT prep. Good luck on your exam(s)!

Thank you for this clarification and conformation as Khan Academy has to follow the rules of the contract.