No, a sentient life wouldn't be able to have advanced technology without an appendage (unless it has magic)
I want to give you an animal on earth that is very smart yet doesn't have any limbs to manipulate its environment: dolphins.
Now imagine dolphins on land. Without any appendages dolphins can only move things by biting it with its mouth or nudging it with its body. It wouldn't be able to use a spear, stone, or stick because it can't move it effectively (a dolphin's neck isn't exactly flexible). So dolphins on land cannot make any advanced tools. Even if somehow they are able to manipulate fire (that they got from lightning), they can't craft anything. On top of that, animals with appendages move faster than those without. The dolphins are going to get murdered.
3 dolphins are trying to forge metal. One dolphin is using its head and mouth to hammer, another is keeping the fire alive by nudging wood to the fire, and the third holding the metal with a stick attached being held by its mouth so it doesn't fall of. It would fail.
Now, in their natural habitats which is underwater, advanced tech wouldn't be available because there is no consistent source of fire.
Appendages are any sort of body parts that are flexible thus able to manipulate the environment. So all limbs are appendages because they can move in a flexible way, even though it can't hold things. (For example, an elephant using its feet to knock down trees.)
I count snakes as having an appendage because their tail and mouth can each hold a different item, so technicaly they can smash 2 rocks together to make fire.