Minimizing pulled open collector output rise time on 74LS09
10% to 90% rise time is approximately 2.2RC so with your 10K pullup a 2.4usec rise time implies around 110pF load. Assuming you used 10% to 90%.
If we check the datasheet for the RP2200 Rigol probe:

That's pretty much what we would expect.
In general, for more than a few MHz, you almost always want to use the x10 position on your probe.
This also illustrates graphically how open-collector (or open-drain) + pullup gates can cause rise time problems with even moderate capacitive loads.