Answered mon own question, thanks to rfc2132
dhcp-option=6,192.168.0.90,192.168.0.98
Cependant, RFC2132 specifies option 5 as a list of name servers et option 6 as a list of domain name servers, et Je suis pas sure what le difference is. Either way, option 6 put them correctly as
nameserver 192.168.0.90
nameserver 192.168.0.98
in /etc/resolv.conf