MATLAB - Read from 2 SPI inputs synchronously
Yes and No.
 Synchronously in development slang means step-by-step execution. Asyncronously mean by some event.

Arduino has only one core. Even if you use interrupt, Arduino can only execute one command at once.

Best way for you I guess would be read both on Arduino and combine into single value to read at once. Just reading both with readDigitalPin  would give huge latency.