You won't be able to get a definitive answer on this because there isn't a single standard for toxic/safe. Bottom line really is that everyone makes their own determination of acceptable risk, what's safe and what's not (here, as with just about everything).
Pines in general do contain some known toxic chemical compounds, but this is also true of other woods that are not uncommonly used in products that see direct food contact (although not specifically spoons for infants, which must be an important detail). As you might or might not have discovered already two things of definite concern here are terpenes and hexanal which are both unquestionably toxic chemicals.
But as a very old saying goes "the dose determines the poison", and this is still a central tenet of toxicology. There are a great number of toxic compounds routinely inhaled and ingested in daily life, and often without ill effects simply because the amounts are too low.
On the plus side, pine resins have been eaten for a very long time and an extract from the needles — "pine needle tea" — is still drunk in some places, and both are very likely to contain terpenes and various aldehydes in addition to hexanal. This suggests the toxicity of these compounds, in the levels found in these small quantities, is of little or no concern.
On the negative side, these are spoons for an infant, and we need to go back to "the dose determines the poison". A great many things that don't make adults and even older children ill are not safe for babies1.
Other reasons to prefer spoons made from different woods
Pinus sylvestris may not be hard enough to wear well. While Scots pine is tougher and more resilient than some other common pines it's still a fairly typical softwood in that is has soft earlywood (the pale stripes in the grain) and harder latewood (the darker stripes).
I would prefer to use a wood of even density myself, just to make something that wears more uniformly and predictably. Good choices would be birch, maple (including soft maple, this is plenty hard enough), sycamore in the UK, beech, and apple or other fruitwoods, including hawthorn and blackthorn if available2.
Bottom line though is that you're the one who has to make the call.
1 Including honey of all things!
2 Do note though that if you're not working these woods green (unseasoned) but are instead shaping them after drying some of these are much much harder than the pine!