Yes, the local-global principle for isogenies is valid for all abelian varieties over all number fields, as a consequence of Faltings' isogeny theorem. The proof for abelian varieties is almost the same as that for elliptic curves. You just need to observe that if A,A' are two g-dimensional abelian varieties over F_q, then the following are equivalent: (i) They are $\mathbb{F}_q$-rationally isogenous. (ii) They have the same characteristic polynomial of Frobenius. (iii) For all $1 \leq i \leq g, \ \#A(\mathbb{F}_{q^i}) = \#A'(\mathbb{F}_{q^i})$. (iv) The Hasse-Weil zeta functions of A and A' coincide. Although I have not checked in order to answer this question, I think it is likely that proofs -- or references to proofs -- of this fact can be found in at least one of the papers --- Waterhouse, William C. Abelian varieties over finite fields. Ann. Sci. École Norm. Sup. (4) 2 1969 521--560. Waterhouse, W. C.; Milne, J. S. Abelian varieties over finite fields. 1969 Number Theory Institute (Proc. Sympos. Pure Math., Vol. XX, State Univ. New York, Stony Brook, N.Y., 1969), pp. 53--64. Amer. Math. Soc., Providence, R.I., 1971. ---