Why Clk Oscillator waveform is not square in the oscilloscope?

Regarding the delay I would suggest something like:

P1: PROCESS (clk_in)

BEGIN

if (delay_cnt_A < xyz)

then

clk_out_a <= '0';

delay_cnt_A <= delay_cnt_A+1;

else

clk_out_a <= clk_in;

end if;

...

END PROCESS;

END behav

Thus the clk_out_a is constant until the delay_cnt_A has reached the configured "xzy" threshold, i.e. the configured number of clk_in cycles are elapsed...

(Just as a rough idea of implementation...)