Depends on the definition of "fry".
- gets very hot.
- goes into thermal shutdown.
- gets so hot it's damaged.
In point of fact, even though the v.regs on Arduino boards tout 1 Amp, you usually
cannot draw anywheres near that amount of current without them getting
#1 = very hot, even if #2 = thermal shutdown doesn't occur, and #3 = not damaged.
IE, the tiny smt parts like the SOT-223 [the usual part found on an Arduino bd] are
rated at 15 degC/watt temperature rise, while the robust TO-220 parts are
3 degC/watt.
Even though they say max operating temp = 150 degC, you're not really gonna want to
let it run anywheres near so hot. 100 degC boiling water will scald your hand nicely,
after all.
If you limit to 80 degC [176 degF, which is still darn hot], ie 55 degC rise, this is
55/15 = 3.6 watts for SOT-223. With Vin = 9V, you get Pd = Vdrop * I, or
I = 3.6W/(9V-5V) = 0.9 Amp.
IOW, if you try to draw fully 1 Amp from the SOT-223, expect it to get very hot.