"Death" dates (actually they are burial dates) are often wrong on the IGI and I think this is one of them. The 1809 burial says "inf" on Brian's burial list and usually an infant is exactly that, not a 4 year old.

I did a quick IGI check for baptisms of Thomas Crain's around 1808-9 and there are quite a few including one to a "T Clague" for Ballaugh, who'd be a better bet to match the "inf" burial.