Under WA state divorce law is it possible to have alimony directly taken out from bank account

you can garnish his bank account if he doesn't pay. i don't know what you mean by s.s. bank account. normally, the social security check would go into his bank account. then you would garnish his bank account.

if your court order specifically allows you to intercept his social security check, in the event of non-payment, a provision i have not seen before, then call DCS and tell them to do it.

the most common collection enforcement mechanism is wage withholding. DCS will garnish his wages. it doesn't sound like he makes wages, though.