A lot of meter depends on the surrounding lines. I agree that on its own, the line you cite can't effectively be scanned as IP, but it could be a trochaic pentameter line with substitution if you put a stress on the AND:
AND a GER / man SOL / dier di RECT / ing HIM
Whether AND can effectively be emphasized depends largely on the line that came before it, however.
I see nothing wrong with
and a / GER man / SOL dier/ di RECT / ing HIM
but it will be anapestic tetrameter with iambic substitutions (or iambic tetrameter with anapestic substitutions -- take your pick).
Again, though, context matters. Would you call
Wordsworth's "London, 1802" trochaic pentameter or iambic? The first two lines start with trochees and there's an initial spondee a few lines down as well, but
most of the poem is in perfect IP.