Answer: Yes it is.
Step-by-step explanation:
The Constitution puts the President at the head of the Executive branch of government and provides that the President should ensure that the laws of the land are faithfully executed.
Seeing as executive orders are issued to members of the executive - which are under the President - and are done to ensure that the laws of the land are carried out, the President is not only following the Constitution's directives in Article II, Section I of the Constitution but doing it within their power as head of the executive.
Executive orders are therefore an implied constitutional power that the President has.