I must be the only one who hasn't caught the I-bonds mania. Yes 9.5% is a crazy interest rate, but it only works if you (1) have $10K lying around in a savings account (2) don't need to touch it in the next 12 months (3) need it in the short term after the 12 months are up. And ultimately you will make a few hundred dollars worth of interest (minus a 3 month interest penalty), all of which will be taxable immediately at your regular short-term rate.
Just put the $10K in VOO instead and forget about it for a few years.