Darwinism, for purposes of this post, is the position that life spontaneously arose from non-living matter and evolved to its present form by a process involving random changes and natural selection.
Creationism is the position that Genesis 1 is a more-or-less literal account of how the universe and life came to be. The most literalist position is called young earth creationism, or YEC. YEC holds that the earth is only about 6,000 years old and that all archeological, astronomical, paleontological, geological, and radiological data to the contrary is either being misconstrued or has been forged by God.
At the other extreme are those who maintain that the scientific view of origins is broadly correct, and that Genesis 1 must be interpreted as broadly as necessary to bring it into alignment with science. Let's call this position old earth creationism, or OEC. Those who follow OEC are generally not Darwinists because they maintain that life did not arise spontaneously and/or that the changes were not entirely random, and/or that the selection was not entirely natural. They believe that God intervened in one or more of these steps. However, OEC is consistent with what I will call quasi-Darwinism, the position that there is no way to tell from the data that Darwinism is false.
There are people in all three of the major Abrahamic religions (Judaism, Christianity, Islam) who are creationists, but this is not the only view. Many Christians believe that Genesis 1 is not a literal account of origins at all, although they still believe in a timeless God who is responsible for the existence of the universe. I don't know if there's a word for this position, but let's call it quasi-creationism.
Quasi-creationism has two main branches which I'll call quasi-deism and theistic quasi-creationism or TQC. Quasi-deism is essentially naturalism with respect to origins (but you can't be a full-on deist and a Christian). You can expect a quasi-deist to hold to some naturalist account of origins, most likely Darwinism. TQC is the position that God does not constrain himself from acting in the world, but that scripture gives no clue about origins other than the claim that God is the creator.
TQC is is the most liberal, skeptical position, the position that has the fewest prior commitments, and therefore the position most open to impartial evaluation of the evidence. TQC is considerably more impartial than naturalism because it is consistent with any account of origins, while naturalism is forced to consider only naturalist accounts. In modern thought, Darwinism is the only possible account of origins that is naturalist, so any threat to Darwinism is a threat to the naturalist's worldview. Most people do not react well to having their worldview challenged, and naturalists are no exception. By contrast, neither Darwinism nor any other account of origins threatens the TQC worldview, so to those of us who embrace TQC, the question of origins is a purely intellectual issue that we can approach impartially and rationally, without philosophical baggage.
Intelligent Design (ID) is a scientific theory that has two main parts: a critique of Darwinism, and a positive claim that life shows the signs of being designed. ID is consistent with no theistic accounts of origins besides TQC and OEC (old earth creationism). It is not consistent with YEC because it is a scientific theory that embraces all the discoveries of archeology, astronomy, paleontology, geology, and radiology that YEC rejects. It is not consistent quasi-deism because it contains an explicit argument against Darwinism which quasi-deism embraces.
So if ID is nothing but creationism in disguise, then it would have to be nothing but OEC in disguise. But OEC does not imply ID because OEC is consistent with quasi-Darwinism and ID is not. Also, ID does not imply OEC because ID, but not OEC, is consistent with alien source of life or ASL, the position that intelligent life evolved on another planet and that the aliens seeded life on earth and have consequently guided evolution. Since ID does not imply OEC and OEC does not imply ID, they are not logically equivalent.
But the question is not really about logical equivalence. Maybe "creationism in disguise" just means that ID is a stalking horse for creationism, that for those who believe in creationism, ID is just a way to try to make creationism more acceptable. There is no question that this is the motivation of some proponents of ID. In fact, it is not unlikely that this is the motivation of the large majority of of proponents of ID. Since OEC is not scientific, this links ID to an unscientific position.
However, while this may arguably be a good reason for scientists to ignore ID, it is not a philosophical argument; it is an ad hominem argument; it attacks ID on the basis of who is making the argument and their motivations rather than on the merits of the argument itself. Ad hominem arguments have no place in philosophy. Ad hominem arguments are only acceptable as counters to arguments from authority. If someone makes an argument that relies on an expert witness or some other authority, where the competence and candor of the authority is an essential part of why the argument is persuasive, then an attack on the competence or motivation of the authority is relevant. But philosophy is not a subject matter where arguments from authority are suitable, and so it is not a subject matter where ad hominem arguments are suitable.
Another argument that one sometimes sees on this forum is the claim that some court in Texas ruled that ID is creationism. However, this is not a philosophical argument either; it is an argument from authority, which, as I just explained, has no place in philosophy.
So to conclude: ID is not logically equivalent to any form of creationism, and the only other arguments linking ID to creationism are either arguments from authority or ad hominem, and as neither form of argument is philosophical, there are no philosophical arguments for the position that ID is nothing but creationism in disguise.