No, there are plans for a separate Scottish defence force, however in practice the defence of this whole island has been guaranteed by NATO (I.e. the USA) for many years now. If defence were the issue, the UK isn't independent as things stand.
The real problem for the Seps is their stated preference for a currency union with RUK. Scotland would have fiscal autonomy but no influence over monetary policy. Within the UK, Scottish politicians have influence over monetary issues and the Bank of England's obligation to act in the interests of the UK as a whole, includes Scotland. Outside of it, they have no influence and the BoE has no obligation to set monetary policy with regards to the needs of the Scottish economy.
Within a few years the result would be the train wreck that is the Eurozone, where policy oS set to favour Germany, with disastrous results for southern states like Greece.