suppose your are currently paying 15% income tax out of $50,000 income
which is $7500/year tax;
now if 9% income tax, $4500 a year income tax
if you spent $30,000 on goods (that is almost $2600/month for goods, do you buy this much food and clothing, internet?), 9% is $2700, the total is $7200. less than 15% tax.