There are a number of things which can affect this but the short answer is that by default the frames will not be dropped, they will be fragmented. The payload is split into smaller pieces and forwarded, then reassembled at the far end.
In the example you give, 9k frames will probably not be received on the switch interface. They'll likely be fragmented by the PC before they're sent out on the network. Windows, Linux, OSX and other operating systems that support Ethernet interfaces have their own MTU at each layer of the network stack and/or protocol involved. If a layer receives a datagram from the layer above it for processing that's larger than that layer can support, it will generally fragment the datagram into an acceptable size. Unless you've explicitly configured the Ethernet MTU on the host for a larger size, the host's MTU for Ethernet is probably set for 1500 and it will send packets of a maximum of that size, regardless of the size of the chunks that are being sent from the FTP server running on the host.
I'm throwing a lot of "probably" and "likely" qualifications in there because, as I noted, there are a number of factors which can affect this. But fragmentation as it goes through the network stack is typical behavior.
