We apologize for the delay:

The ensembl 96 gtf (converted to GRanges on the fly) and fasta (twobit files) been added to AnnotationHub and are currently available in Bioc 3.9

> library(AnnotationHub)
> hub = AnnotationHub()
snapshotDate(): 2019-04-29
> length(query(hub, c("ensembl", "gtf", "release-96")))
[1] 471
> length(query(hub, c("fasta", "release-96", "twobit")))
[1] 799