The thing with market cap is, most of it is decided by the last trade price, which can be very volatile. With deep order book on index and household name like Apple, that volatility doesn't show up until a black swan event like it did in March 2020.
$9B is still small against Apple’s $200B, but fairly large against Intel’s $34B. So yeah I’d be scared.
https://www.apple.com/newsroom/pdfs/FY21_Q2_Consolidated_Fin...
marketable securities are volatile and don't hold their value exactly when there is a liquidity crisis. Even including these securities, totals to about $60B quite shy of either $200B or $1T
The equivalence standard you used is the accounting standard, which means you can get the exact amount in cash overnight if you so desire. It's too strict when considering what financial resources you have in making long term capital investments.