Hi Bella and hi there Danger above me:)
I have to disagree. Aspects between one person's outer (karmic) planets and the other jperson's personal planets are actually a really big deal in a synastry chart.
Sign placements of outer planets take on less significance in a natal chart due to the fact that they move so slowly that those planets can take many years to move through one sign (Pluto for example will spend the next 16 years give or take in Capricorn before it moves completely into Aquarius-and this is the fast part of it's orbit), but house placements are far more personal and so placement of the outer planets within houses takes on greater significance as it points to karma which the person needs to either resolve or manifest in this lifetume. Aspects between personal planets and outer ones in the birth chart, or aspects from outer planets to angles, or aspects to the nodes or the vertex/anti-vertex by either personal or outer planets all point to the individual's karmic debts/destiny. There are other things that you can look at in a chart to point to this, but these will give you a pretty good idea of where this individual's going in life and also where the soul has been previously. The outer planets are our links to the collective unconscious and whatever other Universal intelligence there may be.
Synastry aspects between one person's personal planet and the other's outer planets indicate that the relationship of these two people is a karmic one. There may or may not be past life bonds between the two people, but regardless of whether or not there are, these two people have made a contract with each other on the soul level which they are to fulfill in this lifetime. If this obligation is not resolved, it's very likely that they will continue to work on that karma in future lifetimes until it is. In this particular instance the person with the Pluto placement (aka you) would be instrumental in the transformation of how the person with the Sun placement (him) expresses his Sun sign energy (i.e. the core of who he is). Pluto's powers of transformation are particularly strong in the sign of Scorpio, as it is in the sign which is rules and therefore can express itself most purely there. If this is a young Scorpio male that we're talking about though, you've probably got your work cut out for you, so likely you'll need every ounce of strength that Pluto's got. You'll definitely have a very profound effect on each other, but more to the point, you will likely have a very profound transformative effect on him, for good or for ill. Karmic relationships are not surface relationships. Many people can get by and even be "happy" with relationships which have no outer planet or other karmic ties at all. The thing to remember is that there are higher energies at work here and both people need to tune into those energies and elevate their levels of consciousness in order for this to work. The Pluto person has the responsibility of chanelling this transformative energy but needs to be careful to use this responsibly and not let this power become an ego driven need to control the Sun sign person. The Sun person needs to be willing and capable of letting go of their attachment to ego enough to allow the Pluto person power to manifest this energy and use it. If either person allows themselves to become ego driven, the end results can be painful. If both people can manage to tap into that elevated consciousness, the relationship has the potential of being a spiritual experience for both. Typically, it's some of each though.
EDIT: Hi again Danger:-) Aspects between the outer planets themselves are not considered as important, due to the fact that since they move so slowly entire generations of people can have the same aspect between two (or more) outer planets in their charts. So, sign placements and aspects between outer planets, not as important, no, but aspects from outer planets to personal planets and points and house placements are very important indeed. And for the record, just so you know I didn't TD you. What you said is actually a fairly common thought amongst some astrologers. To be sure, it's not the first time that I've read that point of view. But it's inaccurate. It's just not looking deep enough into the relationship. So, I actually TU'ed you, because up until a certain point, I would have thought the same thing, because that's what I had read as well. However, personal experience and further reading has taught me very different.
For sure though, I would look into those karmic ties with your family, because they will be there. Look to aspects between one person's outer planets and another's personal planets, and aspects to the nodes from either outer or personal planets, and you should find something. Cheers:-)
EDIT #2: Yes, all aspects between outer and personal planets are significant.