However, if I read your post correctly, I think LaplaceTransform is working correctly, in that the Laplace transform of 1 is 1/s.
In[1]:= LaplaceTransform[g'[t], t, s]
Out[1]= -g[0] + s LaplaceTransform[g[t], t, s]
In[2]:= LaplaceTransform[g'[x], t, s]
Out[2]= Derivative[1][g][x]/s
In[3]:= LaplaceTransform[1, t, s]
Out[3]= 1/s