Earned Income Tax Credit Improvement and Simplification Act 201 7 This bill amends the Internal Revenue Code, with respect to the earned income tax credit, to: (1) allow the credit for an individual who has no qualifying children, has attained the age of 21 but not 25, and is not a full-time student; (2) increase the credit rate and amount for individuals with no qualifying children; (3) allow the credit for an individual whose qualifying children do not have valid Social Security numbers; (4) revise eligibility rules relating to married individuals living apart and qualifying children claimed by another family member; and (5) repeal the denial of such credit for taxpayers with excess investment income.