Wonder if a CW diode can be pulsed, giving the same output power

Some laser diodes can work in both CW and pulsed mode efficiently.
I have noticed that the peak power is higher in pulsed mode than in CW mode for some lasers

Lets say there is a 1W 445nm blue laser diode in CW.

If i want to pulse it to 25ns, can it give stable 1W peak power in 25ns?

That should be absolutely no problem. If you possibly intend to increase the laser peak power above the DC rating, it's not only limited by thermal effects. Keeping the specified DC rating as peak power will be always safe, however.