Oh what are the Kirk Session records? Are they Scottish Births / Deaths / Marriages / Census?
I have very little to go on
No. They are the records of the Kirk Sessions, which are the committees that run each church/congregation.
Until about the middle of the 19th century they devoted a lot of their time to attempts to stamp out 'sin' among their congregations. 'Sin' could take all sorts of forms, including drunkenness and profaning the sabbath, but by far the majority was fornication or occasionally adultery. Thus the KS records often contain a lot of information about people accused of 'sin'.
There is no alternative to Scotland's People if you want to see original birth, marriage and death certificates after the start of civil registration. This is exactly that same as in England, Australia, New Zealand and many other parts of the world, apart from the fact that the Scottish ones cost a fraction of what most others do. For example you get 4 Scottish certificates for the same as one English certificate - and they are more informative.
As for the census, transcriptions are widely available. They are of variable quality (FreeCEN is the most accurate and Ancestry the worst) and should always be checked by looking at the original.
If you go to a Latter Day Saints' Family History Library you can view microfilms of most of the pre-1855 Church of Scotland registers of baptisms and banns, and of the 1841 to 1891 (or is it 1901?) census. If the FHL you go to doesn't have the correct films in stock, you can arrange for them to get them for a small rental fee. I beieve that the LDS also have films of birth, marriage and death certificates from 1855 to 1874, and 1881 and 1891, but I have never attempted to see one of those.
If you have only needed to search in Ireland so far you are exceptionally lucky that the available records are free. However they don't include all the church records, and there are very few censuses before 1901 - just a handful from 1851, as far as I know.
