While I'm here: Google uses edns0 client subnet to geo target your client IP.
Try a dig -t txt o-o.myaddr.l.google.com @8.8.8.8 vs the others to see the src IP of the packet sent to Google's DNS server, and any edns0 info that came along with it.
Interestingly, I get 3 different source IPs, BUT! The one from Quad9 is IPv6 and the ones from 8.8/1.1 are IPv4. Google returns an extra TXT record as well with "edns0-client-subnet 172.56.95.0/24". I'm not a DNS pro, so not sure what to make of it.
As 9.9 returned an IPv6, I tested with AAAA records just now - 1.1/8.8 respond with 4x IPs, 9.9 only 1x so it mirrors the A records in spirit.
While I'm here: Google uses edns0 client subnet to geo target your client IP.
Try a dig -t txt o-o.myaddr.l.google.com @8.8.8.8 vs the others to see the src IP of the packet sent to Google's DNS server, and any edns0 info that came along with it.