We have a Site-to-Site VPN setup from our main office to two remote
offices.

When I use a Client-to-Site connection to access the network at the
office, I can't access anything through the Site-to-Site connections.

Is this possible ?

Main Office VPN Tunnel IP is 10.0.9.1

Remote 1 VPN Tunnel is 10.0.9.2

Remote 1 VPN Tunnel is 10.0.9.3

Main office subnet is 10.0.1.x

Remote office 1 is 10.0.2.x

Remote office 2 is 10.0.3.x