Aren't most of the tech workers here part of that 10% and I'd assume they own houses in some of the most expensive areas, so they are technically part of the capital class?

Being a part of the "capital class" does not mean simply having passed a net worth threshold.

It means having sufficient liquid capital that you can invest it in uncertain outcomes, generally without fear of poverty or perhaps any real negative effects on one's life at all.

Owning a very expensive home in a very high cost-of-living place (or even in a not-so-high cost-of-living place) does not place a person in that position.

defining classes is complicated. if you do it based on income percentile it will always be arbitrary and never reflect actual economic relations.

the most accepted way to divide in socialist circles is based off where your income comes from, your relation to capital. if you have to work for someone else thats working class (proletariat), if you can be independent you are professional or middle class, if you own the means of production for others that makes you a capitalist. owning a house is only capital class if you rent it out.

from that pov almost all tech workers are professional or working class. with founder ceos its more complicated because they own capital but also work for themselves through their company so you can take them as either. i guess it depends on if you like that person.