We had exactly the same problem with our Harry, when he was younger and specifically when he was teething...
He chewed through his soft-sided pen and met me at the front door...
Hard-sided pens didn't help either, as he's a bit of an escape artist and always managed to climb out.
We decided that we had to have some sort of a safe-place to put him for the odd time, so we bought a BIG metal crate - big enough for his bed, food, water, toys etc...it's for HIS safety, rather than have the fear of him chewing through cables, wires etc...he didn't like it at first, but he got used to it.
As for all the things he's chewing when you ARE around - I'd say put everything out of reach. We put shoes etc in a (new!) cupboard - everything's picked up and cleared away - as you would with a toddler in the house.
On stuff that you
can't put away - some people swear by Bitter Apples/Cherry spray, others use men's unfragranced roll-on deodorant, others make pastes out of highly spiced sauces and spread it on...
What worked best for me was EXTREME vigilance and a sharp "NO" when Harry started on something that he shouldn't. It would stop him in his tracks - and then I'd give him something 'ok' to chew on instead...we haven't had anything ruined for well over a year now.
Good luck, and hope this helps a little
Sally x