Which A skill for Robin male?

Triangle adept is usually the best for him since it help him with damage output against 2 colors.
I’ve also seen deathblow, but that’s better on high merges

Is that a blade tome?

I would say he uses Raven, Owl and Serpent bit better.
Raven + TA is the easiest.
Owl can be used with atk/def bond, Distant Defence, fury, or a stance skill.
Serpent with the same as owl, minus the bond skill. But it is a very premium skill.

If you really want to go for a blade tome I would pick fury, Deathblow, or fierce stance if you have it

Lastly, any weapon could go with Close Counter, This Robin has just enough def and speed to bait in melee units.