Private-credit lenders are literally shadow banks [1]. But I'd be cautious about linking any shadow banking with crisis. Tons of useful finance occurs outside banks (and governments). One could argue a classic VC buying convertible debt met the definition.

That said, the parallel to 2008 is this sector of shadow banking has a unique set of transmission channels to our banks. The unexpected one being purely psychological–when a bank-affiliated shadow bank gates redemptions, investors are punishing the bank per se.

[1] https://en.wikipedia.org/wiki/Non-bank_financial_institution