I'd be very careful to repair those threads straight, solid and true. Properly repaired threads can be better than the original.
Maybe disconnect all the motor mounts except the side transmission and see if you can tilt the motor far enough (either up or down) to gain good access to the tensioner area so you can do a solid and square thread repair. Once you drill/tap crooked it gets harder to make it right. You should use some type of jig to make sure its repaired square. Maybe try a small block of steel or piece of I-beam with an appropriate sized hole drilled square on a drill press and clamp/secure that to the front of the block somehow to guide your drill straight and true into the stripped tensioner hole.
Fear my paint skillz
If you do a marginal repair and your timing belt fails you may well be buying a new block (and everything else).
Might as well bust that crank bolt loose first if its not already and do a timing belt job?
Always use patience and a proper torque wrench and torque to spec. I've yet to ever strip a thread or break a fastener on my honda.