I can't tell you much about the sea-faring ability of the Almoravids and other Islamic powers that held Morocco prior to the 15th century, though do I get the impression that they were pretty solidly land powers.

What I can tell you is that the winds and currents off the Moroccan coast make visiting the Canaries rather more difficult than you might expect.

The entrance to the Mediterranean is about at the latitude that the easterly equatorial winds meet the westerly upper latitude winds, such that they tend to form a variety of loops in the Atlantic. The Atlas mountains on the African coast direct the winds offshore to basically follow it southwest, and the currents do about the same.

At about the Canaries, the winds start to catch more of the equatorial "trade winds", and head out into the Atlantic. These blow all the way to Brazil and the Caribbean... which is exactly what later Iberian sailors would do to get to the Americas. But getting on a fast track to Brazil isn't what you want to do if you're not really prepared for it. There is a decent way back to shore, though: if you manage to make your way more to the west, you can catch an eddy in the winds that goes out to sea and starts to loop back around, through the Azores and back to Iberia and the entrance to the Mediterranean.

Take a look at https://www.windy.com/?33.248,-14.019,5 to see what those winds are doing today. They're fairly permanent, so it's likely you'll see what I describe above on any given day.

This particular route the Portugese called (once the discovered it) the "volta do mar", or "turn of the sea". It ended up being a middle step to eventual Atlantic crossings, but that's a different story. But while it works, it's not something you want to do unless you're prepared for some significant blue-water sailing. If you don't know this technique, and/or are not prepared to do it, the Canaries are a bit of a trap; easy to get to, but hard to return from by sail.

The other option, of course, is to just ignore the wind and row back. This is likely what the Romans did when they visited the Canaries. Galleys would still have been available in the medieval Mediterranean, and indeed were the principal warship of the time, but were a rather expensive proposition. (And they did rely mostly on wind for long-distance propulsion, making a return under oars a tiring, though possible, affair.)

If the masters of the Moroccan coast indeed had such vessels (and probably they did; I just don't know to what degree), they may have considered it a poor idea to conquer a few useless islands at such a high cost. It was, ironically, much cheaper for the Castillians, and later the Portugese, to visit with sailing ships, once the techniques for return were established, and it was a handy stop for them on the way to very profitable trade centers in sub-Saharan Africa.